US20100222887A1 - Elbow Prosthesis - Google Patents

Abstract

An elbow prosthesis constructed in accordance to one example of the present teachings can include a first stem structure that is operable to be positioned in a first bone of a joint. The first stem structure can include a first stem portion and a cage structure. The first stem portion may be operable to be positioned in the first bone. The cage structure can be formed generally between an inner sidewall and an outer surface. The stem portion can have opposing surfaces that define a disconnect formed entirely through the cage structure from the inner sidewall to the outer surface. A first bearing component can have an exterior cage opposing surface. The first bearing component can be selectively inserted into the cage structure from an insertion position to an installed position. A fastener can be threadably advanced into an engaged position with the cage structure to reduce a gap defined between the opposing surfaces of the disconnect while radially contracting the cage structure around the first bearing.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application is a continuation-in-part of U.S. patent application Ser. No. 12/562,616, filed on Sep. 18, 2009, which is a continuation-in-part of U.S. patent application Ser. No. 12/391,904, filed on Feb. 24, 2009, which is a continuation-in-part of U.S. patent application Ser. No. 11/384,943 filed on Mar. 17, 2006, which is a continuation-in-part of U.S. patent application Ser. No. 10/333,140 filed on Jan. 15, 2003, which is a National Stage of International Application No. PCT/US01/22338 (published as WO 02/05728), filed Jul. 17, 2001, which claims priority to U.S. Provisional Application No. 60/219,103 filed Jul. 18, 2000. Each of these applicants are incorporated herein by reference.
• U.S. patent application Ser. No. 11/780,365 filed on Sep. 19, 2007 which is now U.S. Pat. No. 7,625,406 and U.S. patent application Ser. No. 11/780,370 filed on Sep. 19, 2007 which is now U.S. Pat. No. 7,604,666 disclose related subject matter. These applications are also incorporated by reference.
FIELD
• The present teachings relate generally to prosthetic devices used in arthroplasty and more particularly to a modular elbow prosthesis.
BACKGROUND
• The present teachings relate generally to prosthetic devices used in arthroplasty and more particularly to a modular elbow prosthesis.
• Linked or constrained elbow prostheses are known which comprise simple hinge arrangements, one component of which is attached to the end of the humerus and the other component of which is attached to the end of the ulna. The humeral component includes a shaft, which is cemented into a prepared cavity in the end of the humerus, and the ulnar component includes a shaft, that is cemented to the end of the ulna. The components of the prosthesis are connected together by means of a hinge pin so that the prosthesis allows a single degree of freedom of movement of the ulna relative to the humerus.
• One example of a linked elbow prostheses is disclosed in U.S. Pat. No. 6,027,534 to Wack et al. In several respects, the linked embodiment of the '534 patent is typical of the designs for linked elbow prostheses in that it includes a humeral stem that terminates at a yoke at its distal end, a bearing component, a retaining pin and an ulna stem. The bearing component includes an oversized hole that is aligned with the longitudinal axis of the bearing and adapted to accept the retaining pin in a slip-fit condition. The distal end of the bearing component is coupled to the ulna stem. Despite the relatively widespread use of designs of this type, several drawbacks have been noted.
• One significant drawback concerns the assembly of the elbow prosthesis after the surgeon has cemented the humeral and ulna stems to their respective bones. In using such conventionally configured linked elbow prosthesis devices, it is frequently necessary for the surgeon to drill a fairly large hole through the humerus so that the retaining pin may be inserted to the yoke of the humeral stem and the humeral bearing component. As a high degree of accuracy is typically required to ensure proper alignment between the hole in the humerus and the hole in the yoke of the humeral stem, a significant cost can be associated with this step in the installation of an elbow prosthesis due to the cost of the tooling used and the amount of time required to complete this step. The other method for attaching the prosthetic device includes inserting the device in its linked condition or placing the remaining piece into the yoke prior to fully seating the humeral component into the bone. This later method is typically somewhat difficult, given the limited amount of joint space that is available and the time constraints associated with the use of a PMMA bone cement.
• Unlinked, or unconstrained, elbow prostheses are known which are similar to linked elbow prostheses but do not have a specific component which mechanically couples the humeral and ulnar stems together. Rather, the prosthetic device is held together by the patient's natural soft tissues. One example of an unlinked elbow prostheses is also disclosed in U.S. Pat. No. 6,027,534 to Wack et al. In several respects, the unlinked embodiment of the '534 patent is similar to the linked embodiment discussed above in that it includes a humeral stem that terminates at a yoke at its distal end, a humeral bearing component, a retaining pin, an ulnar bearing component and a ulnar stem. The outer surface of the humeral bearing is contoured to match the contour of the ulnar bearing component. Despite the relatively widespread use of designs of this type, several drawbacks have been noted.
• For instance, a retaining pin that is transverse to the longitudinal axis of the patient is employed, thereby making its removal difficult if a bearing need to be replaced.
SUMMARY
• An elbow prosthesis constructed in accordance to one example of the present teachings can include a first stem structure that is operable to be positioned in a first bone of a joint. The first stem structure can include a first stem portion and a cage structure. The first stem portion may be operable to be positioned in the first bone. The cage structure can be formed generally between an inner sidewall and an outer surface. The stem portion can have opposing surfaces that define a disconnect formed entirely through the cage structure from the inner sidewall to the outer surface. A first bearing component can have an exterior cage opposing surface. The first bearing component can be selectively inserted into the cage structure from an insertion position to an installed position. A fastener can be threadably advanced into an engaged position with the cage structure to reduce a gap defined between the opposing surfaces of the disconnect while radially contracting the cage structure around the first bearing.
• According to additional features, at least one of opposing surfaces of the disconnect is non-linear from the inner sidewall to the outer surface. The inner sidewall of the cage structure can have a first groove and the exterior cage opposing surface can have a second groove that opposes the first groove in the installed position. A lock ring can partially nest within each of the first and second grooves in the assembled position.
• According to still other features, the cage structure can include at least one tabbed entry formed on the inner sidewall that slidably accepts at least one tab formed on the exterior cage opposing surface of the first bearing component in the installed position. The at least one tab and tab entry respectively can cooperate to inhibit rotation of the first bearing around the inner sidewall of the cage structure in the assembled position.
• According to additional features, the inner sidewall can have a first V-shaped cross-section. The exterior cage opposing surface of the first bearing component can have a second V-shaped cross-section that cooperatively engages the first V-shaped cross-section to inhibit medial/lateral movement of the first bearing in the installed position. A second bearing component can be provided that is associated with a second stem structure. The second bearing component can be operable to cooperatively rotate with the first bearing component. The first stem structure can be adapted to be implanted into one of a humerus or ulna. The second stem structure can be adapted to be implanted into the other of the humerus and ulna.
• An elbow prosthesis according to another example of the present teachings can include a stem structure that is operable to be positioned into a bone of a joint. The stem structure can include a stem portion and C-shaped body portion. The stem portion can be operable to be positioned in the bone. The C-shaped body portion can have a first retaining mechanism formed thereon. The elbow prosthesis can further comprise an articulating component that has a second retaining mechanism formed thereon. The articulating component can be rotatably advanced from an insertion position to an assembled position, such that the first and second retaining mechanisms cooperatively interlock to inhibit medial/lateral movement of the articulating component relative to the C-shaped body portion of the stem structure. The first retaining mechanism can comprise outwardly extending rails that are formed on the C-shaped body portion. The first retaining mechanism can further comprise a stop having stop surfaces provided on one end of the rails. The second retaining mechanism can comprise a channel having a geometry that cooperatively receives the rails of the C-shaped body portion. The articulating component can comprise a catch having catch surfaces that engage the stop surfaces in the assembled position. A plate and a fastener can further be provided. The fastener can extend through a passage in the plate that threadably couples to the stem portion. The plate can inhibit rotation of the articulating component from the assembled position to the insertion position. A plurality of articulating components can be provided each having various geometries. One of the articulating components from the plurality can be selected and coupled to the stem structure according to a given patient's specific needs.
• An elbow prosthesis constructed in accordance to other features of the present teachings can include a stem structure operable to be positioned in a bone of a joint. The stem structure can include a stem portion and a C-shaped body portion. The stem portion can be operable to be positioned in the bone. The C-shaped body portion can have a first retaining mechanism thereon. The elbow prosthesis can further comprise an articulating component having a second retaining mechanism formed thereon. One of the first and second retaining mechanisms comprises a rail and the other of the first and second mechanisms comprises a groove. The articulating component is advanced from an insertion position to an installed position, such that the first and second retaining mechanisms cooperatively interlock to inhibit medial/lateral movement of the articulating component relative to the C-shaped body portion of the stem structure.
• According to other features, the articulating component can comprise a bearing portion and a rail. The rail can have a first end that includes a plate and a second end that includes a hook. The plate can include an eyelet adapted to receive a fastener therethrough. The fastener can threadably couple the articulating component to the stem structure. The hook can cooperatively engage an end of the stem portion at the groove.
• Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
DRAWINGS
• Additional advantages and features of the present teachings will become apparent from the subsequent description and the appended claims, taken in conjunction with the accompanying drawings, wherein:
• FIG. 1 is an exploded perspective view of a linked prosthetic joint kit constructed in accordance with the teachings of a first aspect of the present teachings;
• FIG. 1A is an exploded perspective view of a linked prosthetic joint kit similar to that ofFIG. 1 but constructed in accordance with a first alternate embodiment of the first aspect of the present teachings;
• FIG. 2 is a longitudinal cross-sectional view of the linked prosthetic joint kit ofFIG. 1 implanted in the arm of a person;
• FIG. 3 is a cross-sectional view taken along the line3-3 ofFIG. 2;
• FIG. 4 is an exploded perspective view of an unlinked prosthetic joint kit constructed in accordance with the teachings of a first aspect of the present teachings;
• FIG. 5 is a longitudinal cross-sectional view of the unlinked prosthetic joint kit ofFIG. 4 implanted in the arm of a person;
• FIG. 6 is an exploded plan view of a linked prosthetic joint kit constructed in accordance with a second alternate embodiment of the first aspect of the present teachings;
• FIG. 7 is an enlarged portion of the linked prosthetic joint kit ofFIG. 6;
• FIG. 8 is an exploded plan view of a linked prosthetic joint kit constructed in accordance with a third alternate embodiment of the first aspect of the present teachings;
• FIG. 9 is a exploded side elevation view of a portion of a joint kit constructed in accordance with the teachings of a second aspect of the present teachings;
• FIG. 10 is an exploded side elevation view of a portion of a joint kit constructed in accordance with a first alternate embodiment of the second aspect of the present teachings;
• FIG. 11 is an exploded side elevation view of a portion of a joint kit constructed in accordance with a third alternate embodiment of the second aspect of the present teachings;
• FIG. 12 is a longitudinal cross-sectional view of a portion of a joint kit constructed in accordance with a fourth alternate embodiment of the second aspect of the present teachings;
• FIG. 13 is an exploded side elevation view of a portion of a joint kit constructed in accordance with a fifth alternate embodiment of the second aspect of the present teachings;
• FIG. 14 is a cross-sectional view taken along the line14-14 ofFIG. 13;
• FIG. 15 is a cross-sectional view of a portion of a joint kit constructed in accordance with a sixth alternate embodiment of the second aspect of the present teachings;
• FIG. 16 is an exploded side elevation view of a portion of linked prosthetic joint kit constructed in accordance with the teachings of various embodiments of a third aspect of the present teachings;
• FIG. 17 is a cross-sectional view taken along the line17-17 ofFIG. 16;
• FIG. 18 is a cross-sectional view taken along the line18-18 ofFIG. 16;
• FIG. 19A through 19D are side elevation views of bearing inserts constructed with varying degrees of varus/valgus constraint;
• FIG. 20 is an exploded side elevation view of a portion of a linked prosthetic joint kit constructed in accordance with the teachings of a first alternate embodiment of the third aspect of the present teachings;
• FIG. 20B is an exploded side elevation view of a portion of a linked prosthetic joint constructed in accordance with the teachings of second alternate embodiment of the third aspect of the present teachings;
• FIG. 20C is a side view of an alternately constructed pin for linking the stem structures of the second alternate embodiment of the third aspect of the present teachings;
• FIG. 21 is a bottom plan view of a portion of the linked prosthetic joint kit ofFIG. 20 illustrating the bearing insert in greater detail;
• FIG. 22 is a side elevation view of a portion of the linked prosthetic joint kit ofFIG. 20 illustrating the clip member in greater detail;
• FIG. 23 is a longitudinal cross-sectional view of a linked prosthetic joint kit constructed in accordance with the teachings of a various embodiment of a fourth aspect of the present teachings;
• FIG. 24 is a top plan view of the linked prosthetic joint kit ofFIG. 23;
• FIG. 25 is an exploded top plan view of a linked prosthetic joint kit constructed in accordance with the teachings of a various embodiment of a fifth aspect of the present teachings;
• FIG. 26 is a longitudinal cross-sectional view of the linked prosthetic joint kit ofFIG. 25;
• FIG. 27 is a longitudinal cross-sectional view similar to that ofFIG. 2, but illustrating the stem with an integrally-formed flange for compressing a bone graft;
• FIG. 28 is a side view illustrating a stem with an integrally-formed, resilient flange for compressing a bone graft;
• FIG. 29 is a longitudinal cross-sectional view similar to that ofFIG. 2, but illustrating the stem ofFIG. 28;
• FIG. 30 is a longitudinal cross-sectional view similar to that ofFIG. 29, but illustrating the resilient flange as being fixedly but removably coupled to the stem;
• FIG. 31 is a partially broken-away exploded perspective view illustrating an alternative coupling means for coupling the modular flange to the stem;
• FIG. 32 is a longitudinal cross-sectional view similar to that ofFIG. 2, but illustrating the alternative coupling means ofFIG. 31;
• FIG. 33 is a view similar to that ofFIG. 31 but illustrating a second alternative coupling means;
• FIG. 34 is a view similar to that ofFIG. 31 but illustrating a third alternative coupling means;
• FIG. 35 is a longitudinal cross-sectional view similar to that ofFIG. 2, but illustrating the alternative coupling means ofFIG. 34;
• FIG. 36 is an exploded perspective view of a prosthesis according to various embodiments;
• FIG. 37 is a detailed cross-sectional view of an assembled prosthesis according to various embodiments;
• FIG. 38 is an exploded plan view of a prosthesis according to various embodiments;
• FIG. 39 is a detailed environmental view of a prosthesis implanted in an anatomy according to various embodiments;
• FIG. 40 is a perspective view of a stem structure with a modular flange;
• FIG. 41 is a perspective view of a stem structure with a modular flange;
• FIG. 42 is an exploded perspective view of an elbow prosthesis, according to various embodiments;
• FIG. 43 is a detail plan view of a first and second fastener;
• FIG. 44 is a detail cross-sectional view of the elbow prosthesis ofFIG. 42 along line44-44;
• FIG. 45 is an exploded perspective view of a stem structure with modular bearing member;
• FIG. 46 is a plan view of an assembled stem structure ofFIG. 45 in a first orientation;
• FIG. 47A is a plan view of an assembled stem structure ofFIG. 45 in a second orientation;
• FIG. 47B is a cross-sectional view of the assembled stem structure ofFIG. 47A alongline47B-47B;
• FIG. 48 is an exploded perspective view of a stem structure with modular bearing member;
• FIG. 49 is a plan view of an assembled stem structure ofFIG. 48 in a first orientation;
• FIG. 50A is a plan view of an assembled stem structure ofFIG. 48 in a second orientation;
• FIG. 50B is a cross-sectional view of the assembled stem structure ofFIG. 50A alongline50B-50B;
• FIG. 51 is an exploded perspective view of a stem structure with modular bearing member;
• FIG. 52A is a plan view of an assembled stem structure ofFIG. 51;
• FIG. 52B is a cross-sectional view of the assembled stem structure ofFIG. 52A alongline52B-52B;
• FIG. 53 is a perspective view of a stem assembly constructed in accordance to additional features of the present teachings;
• FIG. 54 is an exploded perspective view of the stem assembly ofFIG. 53;
• FIG. 55 is a cross-sectional view of the stem assembly showing a bearing member in an insertion position relative to a stem member;
• FIG. 56 is a cross-sectional view of the stem assembly ofFIG. 55 and shown during assembly of the bearing into a cage of the stem component;
• FIG. 57 is a cross-sectional view of the stem assembly ofFIGS. 55 and 56 and shown with the bearing in an assembled position relative to the stem component;
• FIG. 58 is a cross-sectional view of the stem assembly prior to insertion of a fastener into the stem component;
• FIG. 59 is a cross-sectional view of the stem assembly ofFIG. 58 and shown with the fastener threadably assembled;
• FIG. 60 is a perspective view of a stem component constructed in accordance to additional features;
• FIG. 61 is a perspective view of a stem assembly constructed in accordance to additional features of the present teachings;
• FIG. 62 is an exploded perspective view of the stem assembly ofFIG. 61 and shown with an alternate bearing;
• FIG. 63 is a cross-sectional view of the stem component and bearing ofFIG. 62 and shown in an insertion position;
• FIG. 64 is a cross-sectional view of the bearing and stem component ofFIG. 63 and shown with the bearing partially inserted into a cage structure of the stem component during an assembly step;
• FIG. 65 is a cross-sectional view of the bearing and stem component ofFIGS. 63 and 64 and shown with the bearing in an assembled position relative to the stem component;
• FIG. 66 is a cross-sectional view of the stem assembly ofFIG. 62 and shown with a fastener being threadably assembled into the stem component;
• FIG. 67 is a cross-sectional view of the stem assembly ofFIG. 66 and shown with a fastener threaded into the stem component in an assembled position;
• FIG. 68 is a perspective view of a modular unlinked ulnar stem assembly constructed in accordance to one example of the present teachings;
• FIG. 69 is an exploded perspective view of portions of the ulnar stem assembly ofFIG. 68;
• FIGS. 70-72 is an assembly sequence showing an articulating component or bearing being selectively secured to the stem component;
• FIG. 73 is a perspective view of a modular unlinked ulnar stem assembly constructed in accordance to additional features of the present teachings;
• FIG. 74 is an exploded perspective view of portions of the ulnar stem assembly ofFIG. 73;
• FIG. 75 is an exploded perspective view of portions of an unlinked ulnar stem assembly having a retaining mechanism constructed in accordance to additional features of the present teachings;
• FIGS. 76-77 are an assembly sequence showing the modular articulating component being coupled to the stem component according to one example;
• FIGS. 78-79 are an assembly sequence showing an articulating component and stem component according to additional features and illustrating an exemplary sequence of coupling the articulating component to the stem component;
• FIGS. 80 and 81 illustrate an exemplary assembly sequence of another unlinked ulnar stem assembly according to additional features;
• FIGS. 82 and 83 illustrate an exemplary assembly sequence of another unlinked ulnar stem assembly according to additional features;
• FIG. 84 is a perspective view of an exemplary bearing removal tool kit constructed in accordance to one example of the present teachings;
• FIG. 85 is a medial perspective view of an exemplary ulna stem component and bearing member shown with a first tool of the bearing removal tool kit slidably inserting extractor pins according to one example;
• FIG. 86 is a detailed perspective view of a pair of extractor pins after being located into respective depressions of the bearing member by the first tool;
• FIGS. 87 and 88 are an exemplary sequence illustrating a second tool used to further advance the extractor pins around the lock ring to compress the lock ring into the groove of the ulna bearing;
• FIGS. 89 and 90 are an exemplary sequence illustrating an extractor plate used to concurrently advance a plurality of extractor pins across the lock ring to compress the lock ring into the groove of the ulna bearing according to additional features; and
• FIGS. 91 and 92 are an exemplary sequence illustrating a third tool urging the bearing member out of the cage structure of the ulna stem according to one example of the present teachings.
DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS
• The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.
• With reference toFIGS. 1,2 and3 of the drawings, a linked prosthetic joint device constructed in accordance with the teachings of a first aspect is generally indicated byreference number10. Although the particular prosthesis illustrated and discussed relates to a prosthesis for use in reconstructing an elbow, it will be understood that the teachings have applicability to other types of linked and unlinked prosthetic devices. As such, the scope of the present teachings will not be limited to applications involving elbow prosthesis but will extend to other prosthetic applications.
• In the particular embodiment illustrated, linked prosthetic joint10 is shown to include afirst stem structure12, asecond stem structure14, afirst bearing component16, asecond bearing component18, amodular flange20 and atissue fastener22.First stem structure12 includes aproximal portion30 and adistal portion32.Proximal portion30 includes astem member34 which is adapted to fit within themedullary canal36 of ahumerus38.Distal portion32 includes a generallyU-shaped member40 which is fixedly coupled to the distal end ofproximal portion30.U-shaped portion40 includes a pair of spaced-apart legs orfurcations42. A threadedfastener aperture44 extends perpendicularly through each of thefurcations42.
• Second stem structure14 includes adistal portion50 which is adapted to fit within themedullary canal52 of anulna54.Second stem structure14 also includes aproximal portion56 which is coupled tosecond bearing component18. In the particular embodiment illustrated,second bearing component18 is fixedly coupled tosecond stem structure14. However,second bearing component18 may also be releasably coupled tosecond stem structure14 as shown inFIGS. 9 through 12.
• First bearingcomponent16 includes a pair ofcondyle portions60, apin portion62 and a pair offasteners64.Condyle portions60 andpin portion62 are formed from a suitable material, such as cobalt chromium alloy. Eachcondyle portion60 is shown to include a spherically-shapedbearing portion66, slottedaperture68, apin aperture70 and a mountingaperture72. The pair of spherically shaped bearingportions66 collectively form a first bearing surface.Pin aperture70 is sized to receive an end ofpin portion62 to permitpin portion62 to slidingly engagecondyle portions60.Pin62 can also be fixedly coupled with one of saidcondyle portion60 and slidingly engage second of saidcondyle portion60. Each of the slottedapertures68 is sized to slidingly engage one of thefurcations42.
• Second bearing component18 is shown to include acage portion80 which is fixedly coupled to theproximal portion56 ofsecond stem structure14 and a bearingmember82 which is fixedly coupled to thecage portion80. Bearingmember82 includes a pair ofspherical bearing portions84 which are configured to engage the spherically shaped bearingportions66 of thecondyle portions60. The pair of spherical bearing surfaces84 collectively form a second bearing surface that mates with the first bearing surface. Bearingmember82 also includes a throughhole86 which is adapted to receivepin portion62, preferably without transmitting load therebetween (i.e.,pin portion62 preferably does not contact the surfaces of through hole86). In the particular embodiment illustrated, bearingmember82 is fabricated from polyethylene which has been molded tocage portion80. Alternatively, bearingmember82 may be fabricated from any other appropriate material such as a stainless steel, ceramic, pyrolytic carbon, cobalt chrome (CoCr) etc.
• To use linked prosthetic joint10,first stem structure12 is implanted inhumerus38 such thatproximal portion34 is located in themedullary canal36 of thehumerus38 as shown inFIG. 2.Second stem structure14 is similarly implanted inulna54 such thatdistal portion50 is located in themedullary canal52.Pin portion62 is next inserted to thepin aperture70 of one of thecondyle portions60 and the opposite end ofpin portion62 is placed throughhole86 and into thepin aperture70 of the other one of thecondyle portions60.Second bearing component18 is positioned adjacent thedistal portion32 offirst stem structure12, furcations42 are aligned to their respective slottedaperture68 andcondyle portions60 are slidingly engaged tofurcations42.Fasteners64 are inserted through theirrespective mounting apertures72 and threadably engaged to their threadedfastener aperture44. When fully seated, each of thefasteners64 extends through itsrespective furcation42 to preventcondyle portion60 from rotating relative to thefurcation42. At this point, first andsecond bearing components16 and18 hingedly couple first andsecond stem structures12 and14 together in a linked or constrained manner.
• Construction of linked prosthetic joint10 in this manner is highly advantageous in that it permits the surgeon to insert the first andsecond stem structures12 and14 prior to or after assembling linked prosthetic joint10, as well as permits linked prosthetic joint10 to be assembled in a relatively small space as compared to most of the other prosthetic joints that are known in the art. Furthermore, the spherical configuration of first and second bearing surfaces66 and84 permits the load which is transmitted through linked prosthetic joint10 to be spread out over a relatively large area, rather than concentrated at a single point or over a line of contact to thereby improve the durability of linked prosthetic joint10.
• Modular flange20 may be employed to increase the resistance offirst stem structure12 to rotation withinmedullary canal36. InFIGS. 1 and 2,modular flange20 is shown to include an internally threadedfastener90, and a unitarily formedflange structure92 having amount member94 and aflange member96.Mount member94 includes a locatingcylinder94awhich is fixedly coupled toflange member96 at its base and an externally threadedfastener94bwhich is coupled to an opposite side of locatingcylinder94a. A mountinghole98, which is sized to receivefastener94b, extends through internally threadedfastener90. Abore100 formed through thebase102 ofU-shaped portion40 has afirst portion104 which is tapered at one end to engage the edges of internally threadedfastener90 andsecond portion106 which is counter bored at the other end to engage the locatingcylinder94aofmount member94. Internally threadedfastener90 is threadably engaged tofastener94bto fixedly but removably couplemodular flange20 tofirst stem structure12.
• Modular flange20 may be employed to generate a clamping force which clamps aportion108 of thehumerus38 between theproximal portion34 of thefirst stem structure12 and theflange member96. Preferably, abone graft110 is employed in conjunction withmodular flange20 such that the clamping force produced bymodular flange20 is also transmitted tobone graft110 to promote the attachment ofbone graft110 tohumerus38 and the subsequent growth ofbone graft110. Those skilled in the art will understand that alternatively, a flange (not shown) which is unitarily formed withfirst stem structure12 may be incorporated into linked prosthetic joint10 to thereby increase the resistance offirst stem structure12 to rotation withinmedullary canal36. However, a flange which is unitarily formed withfirst stem structure12 could not be employed to generate a clamping force which clamps aportion108 of thehumerus38 between theproximal portion34 of thefirst stem structure12 and the flange.
• Tissue fastener22 is shown inFIGS. 1 and 2 to be a device for attaching soft tissue, such astendons130, to linked prosthetic joint10. In this regard, the specific configuration of tissue fastener is beyond the scope of this disclosure. Examples of suitable tissue fasteners are discussed in U.S. Pat. Nos. 5,380,334, 5,584,835, 5,725,541, 5,840,078 and 5,980,557 which are hereby incorporated by reference as if fully set forth herein.
• In the particular embodiment illustrated,tissue fastener22 is shown to include atissue clamp132 and a threadedfastener134.Tissue clamp132 includes anannular base136 and a pair ofprongs138.Prongs138 are forced through the soft tissue (e.g. tendons130). Threadedfastener134 is inserted through a hole inbase136 and threadably engaged tosecond stem structure14 to fixedly but releasablycouple tissue fastener22 and the soft tissue tosecond stem structure14. Those skilled in the art will understand thattissue fastener22 may also be used in conjunction withfirst stem structure12.
• InFIG. 1A, a linked prosthetic joint device constructed in accordance with the teachings of an alternate embodiment of the first aspect of the present teachings is generally indicated byreference numeral10a. Linked prosthetic joint10ais shown to includefirst stem structure12,second stem structure14,first bearing component16a,second bearing component18a,modular flange20 andtissue fastener22.
• First bearingcomponent16ais similar tofirst bearing component16 in all respects except that it is unitarily formed. Accordingly,pin portion62ais not removableform condyle portions60a.Second bearing component18ais similar tosecond bearing component18 in all respects except that aninsertion aperture150 extends form throughhole86aoutwardly through bearingmember82aandcage portion80a. Accordingly,insertion aperture150 renders the area ofsecond bearing surface84asomewhat smaller thansecond bearing surface84. Second bearing surface84ais otherwise identical tosecond bearing surface84.
• To use linked prostheticjoint device10a, first andsecond stem structures12 and14 are initially inserted to the humerus and ulna andfirst bearing component16ais fastened to thefirst stem structure12 using techniques similar to that discussed above for prostheticjoint device10. First bearingcomponent16ais then positioned adjacentsecond bearing component18asuch thatpin portion62ais ininsertion aperture150.Pin portion62ais then forced toward throughhole86a. Thedistal end152 ofinsertion aperture150 is smaller thanpin portion62ato permit bearingmember82ato engagepin portion62ain a snap fit manner, so as to inhibit the unintentional withdrawal ofpin portion62afrom throughhole86a. As discussed above, throughhole86ais preferably larger in diameter thanpin portion62a. At this point, first andsecond bearing components16aand18ahingedly couple first andsecond stem structures12 and14 together in a linked manner.
• InFIGS. 4 and 5, an unconstrained or unlinked prosthetic joint device constructed according to a first aspect of the present teachings is generally indicated byreference number10′. Unlinked prosthetic joint10′ is shown to include afirst stem structure12, asecond stem structure14, afirst bearing component16′, asecond bearing component18′, amodular flange20 and atissue fastener22. Unlinked prosthetic joint10′ is shown to be operatively associated with ahumerus38′ and anulna54′ (FIG. 5), but those skilled in the art will understand that the teachings of the present teachings have application to prosthetic joints for other applications and as such, the scope of the present teachings will not be limited to elbow joints.
• First bearingcomponent16′ is similar tofirst bearing component16 in that it includes a pair ofcondyle portions60′ and apin portion62′. However,first bearing component16′ is preferably unitarily formed withpin portion62′ extending between the spherically-shapedbearing portions66′ and fixedly coupling the spherically-shapedbearing portions66′ thereto. Likefirst bearing component16, each of thecondyle portions60′ offirst bearing component16′ includes a slottedaperture68 and afastener aperture72. Spherically shaped bearingportions66′ collectively form a first bearing surface. Likefirst bearing component16,first bearing component16′ may be made from any appropriate bearing material, such as cobalt chromium alloy.
• Second bearing component18′ is similar tosecond bearing component18 in that it includes acage portion80′ which is fixedly coupled to theproximal portion56 ofsecond stem structure14 and a bearingmember82′ which is fixedly coupled to thecage portion80′. For purposes of clarity, bearingmember82′ has not been shown in cross section inFIG. 5. Bearingmember82′ includes spherical bearing surfaces84′ which are adapted to engage the spherically-shapedbearing portions66′ of thecondyle portions60′. The pair of bearingsurfaces84′ collectively form a second bearing surface that mates with the first bearing surface. Bearingmember82′ also includes a raisedportion160 which is adjacent the spherical bearing surfaces84′ and configured to clearpin portion62′, preferably without transmitting load therebetween (i.e.,pin portion62′ preferably does not contact the surfaces of raised portion160). In the particular embodiment illustrated, bearingmember82′ is fabricated from polyethylene which has been molded tocage portion80. Alternatively, bearingmember82′ may be fabricated from any other appropriate material such as a cobalt chromium alloy, ceramics, or stainless steel.
• To use unlinked prosthetic joint10′,first stem structure12 is implanted inhumerus38′ such thatproximal portion34 is located in themedullary canal36′ as shown inFIG. 5.Second stem structure14 is similarly implanted inulna54′ such thatdistal portion50 is located in themedullary canal52′. First bearingcomponent16′ is next positioned adjacent thedistal portion32 offirst stem structure12 andfurcations42 are engaged to slottedapertures68.Fasteners64 are inserted through theirrespective mounting apertures72 and threadably engaged to their threadedfastener aperture44. When fully seated, each of thefasteners64, extends through itsrespective furcation42 to prevent its associatedcondyle portion60′ from rotating relative to thereto. The proximal end of theulna54′ is positioned adjacent the distal end of thehumerus38′ such that thepin portion62′ is proximate the raisedportion160 and the spherically-shapedbearing portions66′ of thecondyle portions60′ engage thespherical bearing surface84′. At this point, first andsecond bearing components16′ and18′ are coupled together in an unconstrained or unlinked manner (i.e., held in position by the soft tissues of the elbow). Construction of unlinked prosthetic joint10′ in this manner provides many of the same advantages as mentioned above for linked prosthetic joint10, such as the ability of first and second bearing surfaces16′ and18′ to spread out the load that is transmitted through unlinked prosthetic joint10′ over a relatively large area, rather than concentrate the load at a single point or over a line of contact to thereby improve the durability of unlinked prosthetic joint10′.
• As a surgeon may not always know prior to beginning an operation whether a patient would be better served by a linked or an unlinked joint prosthesis and as it is also occasionally necessary to convert an unlinked joint prosthesis to a constrained joint prosthesis, or vice versa, after implementation and use for a period of time, it is highly desirable that the joint prosthesis be modular so as to provide the surgeon with a high degree of flexibility which may be achieved in a relatively simple and cost-effective manner.
• InFIGS. 6 and 7, a linked prosthetic joint constructed in accordance with a second aspect of the present teachings is generally indicated byreference numeral10b. Linked prosthetic joint10bis shown to includefirst stem structure12, athird stem structure180,first bearing component16, athird bearing component182.Third stem structure180 is similar tosecond stem structure14 in that it includes adistal portion184 which is adapted to fit within the medullary canal of an ulna. Theproximal portion186 ofthird stem structure180 is coupled tothird bearing component182.
• Third bearing component182 is similar tosecond bearing component18 in that it includes acage portion190 and a bearingmember192.Cage portion190 is fixedly coupled to theproximal portion186 ofthird stem structure180.Bearing member192 is fixedly coupled tocage portion190.Bearing member192 includes a pair of spherical bearing surfaces194 which are configured to engage the spherically-shapedbearing portions66 of thecondyle portions60 and a throughhole196 which is configured to receivepin portion62, preferably without transmitting load therebetween (i.e.,pin portion62 preferably does not contact the surfaces of through hole196).Bearing member182 also includes a lateral buttress200. Lateral buttress200 includes asupplementary bearing surface201 which is configured for receiving acapitellum202 of thehumerus204. In the particular embodiment illustrated,third bearing component182 is fixedly coupled tothird stem structure180 and as such, the combination of thesecond stem structure14 andsecond bearing component18 is interchangeable with the combination of thethird stem structure180 and thethird bearing component182. However, those skilled in the art will understand that second andthird bearing components18 and182 may also be releasably coupled to a stem structure, thereby eliminating the need for athird stem structure180 which would otherwise be identical tosecond stem structure14. Those skilled in the art will also understand that the lateral buttress may alternatively be coupled directly to thethird stem structure180, being either releasably attached thereto or integrally formed therewith.
• InFIG. 8, another linked prosthetic joint constructed in accordance with the teachings of a second aspect of the present teachings is generally indicated byreference numeral10c. Linked prosthetic joint10cis shown to includefirst stem structure12,second stem structure14, afourth stem structure220,second bearing component18, afourth bearing component222 and afifth bearing component224.Fourth stem structure220 includes adistal end226 which is adapted to fit within the medullary canal of a radius and aproximal end228 which is fixedly coupled tofourth bearing component222.Fourth bearing component222 includes afourth bearing surface230.
• Fifth bearing component224 is similar tofirst bearing component16 in that it includes, for example, a pair ofcondyle portions60 and apin portion62 which permits first andfifth bearing components16 and224 to be interchangeable. However,fifth bearing component224 also includes alateral extension240 which is adapted to replace at least a portion of the capitellum of the humerus.Lateral extension240 defines afifth bearing surface242 which is configured to mate withfourth bearing surface230. Preferably, at least a portion of each of the fourth and fifth bearing surfaces230 and242 is spherically shaped to permit loads transmitted therebetween to be spread out over a relatively large area, rather than be concentrated at a single point or along a line of contact.
• InFIG. 9, a portion of a modular prosthetic joint kit constructed in accordance with the teachings of a second aspect of the present teachings is generally indicated byreference numeral10d. Modular prostheticjoint kit10dis shown to includesecond stem structure14d,second bearing component18d,second bearing component18eand afastener250.
• Second bearing components18dand18eare similar tosecond bearing components18 and18′, respectively, but are shown to be separable fromsecond stem structure14d.Second bearing components18dand18ealso include akeel member252, aclip member254 and afastener aperture256 which are formed incage portions80dand80e, respectively.Keel member252 extends circumferentially around at least a portion of the perimeter of each of thecage portions80dand80ebetweenclip member254 andfastener aperture256.Clip member254 includes afirst portion258 which extends generally perpendicularly outward from its associated cage portion and asecond portion260 which is coupled to the distal end offirst portion258.Second portion260 extends generally outwardly and away fromfirst portion258.Fastener aperture256 is located across fromclip member254 and is sized to receivefastener250.
• Second stem structure14dis similar tosecond stem structure14 in that it includes adistal end50 which is adapted to fit within the medullary canal of an ulna.Second stem structure14dalso includes aproximal portion56dhaving akeel slot264, ahook structure266 and an internally threadedfastener aperture268.Keel slot264 is a slot that is sized to receivekeel member252 in a slip fit manner.Keel slot264 andkeel member252 cooperate to resist relative medial/lateral motion of cage portion (e.g.80d) relative tosecond stem structure14d.Hook member266 is generally U-shaped and defines aclip aperture270 which is sized to receiveclip member254.
• To use modular prostheticjoint kit10d, thedistal end50 ofsecond stem structure14dis inserted in the medullary canal of the ulna. The modularity of the prostheticjoint kit10dpermits the surgeon to assess the patient's elbow to determine if the patient would be better served by a linked or an unlinked joint prosthesis. Once a decision has been made as to which type of joint prosthesis would better serve the patient, the surgeon selects an appropriate one of thesecond bearing components18dand18e, places itsclip member254 into theclip aperture270, pivots the cage portion (i.e.80d) toward theproximal end56dof thesecond stem structure14dto engage thekeel member252 into thekeel slot264, inserts thefastener250 through thefastener aperture256 and threadably engages thefastener250 to the internally threadedfastener aperture268 to fixedly but releasably couple thesecond stem structure14dwith the selected one of thesecond bearing components18dand18e.
• Those skilled in the art will understand thatsecond bearing components18dand18emay be coupled tosecond stem structure14din various other manners as illustrated inFIGS. 10 through 15. InFIG. 10,second bearing component18fis shown to include a generally L-shapedtray portion280 which is fixedly coupled tocage portion80f.Tray portion280 includes akeel slot282 and afastener aperture284.Keel slot282 is operable for receiving akeel member286 formed into theproximal end56fofsecond stem structure14f.Fastener aperture284 is operable for receiving afastener288 which may be threadably engaged to an internally-threadedfastener aperture290 in theproximal end56fofsecond stem structure14fto thereby permitsecond bearing component18fandsecond stem structure14fto be fixedly but releasably coupled.
• When coupled together,keel slot282 andkeel member286 cooperate to resist relative medial/lateral motion ofcage portion80frelative tosecond stem structure14f. Additionally,tray portion280 cooperates with an L-shapedflange292 to which it abuts to further resist relative rotation betweensecond stem structure14fandcage portion80f.
• InFIG. 11,second bearing components18gand18hare shown to include astem member300 which extends from theirrespective cage portions80gand80h.Stem member300 is engageable with astem aperture302 formed into theproximal end56gofsecond stem structure14g. As shown inFIG. 12,stem member300′ may alternatively be incorporated into theproximal end56jofsecond stem structure14jand stemaperture302′ may be formed intocage portion80jofsecond bearing component18j.
• To provide the surgeon with additional flexibility,second bearing component18his shown inFIG. 11 to be slightly longer thansecond bearing component18g(i.e. the distances from the centerline of bearingmember82 to the confrontingsurface304 of theirrespective cage portions80gand80his shorter forsecond bearing component18g). This variation betweensecond bearing components18gand18hpermits the surgeon to adjust the length ofprosthesis10gto take into account the physical characteristics of the patient's arm.
• Modularity may also be incorporated intofirst stem structure12kas shown inFIGS. 13 and 14.First stem structure12kis shown to include astem member320 and ayoke member322. Theproximal end324 ofstem member320 is adapted to fit within the medullary canal of a humerus and thedistal end326 ofstem member320 terminates at adovetail aperture328 having a pair of inwardly taperingwalls330 and atapered retaining wedge332. An internally threadedfastener aperture334 extends through retainingwedge332.Yoke member322 is shown to be similar to thedistal end32 offirst stem structure12 as it includes furcations42 and threadedfastener apertures44.Yoke member322 also includes adovetail member338 having a pair of outwardly taperingsurfaces340, awedge slot342 and a throughhole344.Dovetail member338 is configured to mate withdovetail aperture328 such that engagement of retainingwedge332 to theupper surface346 ofwedge slot342 forces taperedsurfaces340 against a respective one of the inwardly taperingwalls330. Afastener350 is inserted throughhole344 and threadably engaged to internally threadedfastener aperture334 to fixedly but releasablycouple yoke member322 and stemmember320 together.
• Referring back toFIG. 11,second bearing components18gand18hare also shown to include a pair oftang members360. Each of thetang members360 extends outwardly from its respective cage portion (i.e.,80g) and in the particular embodiment illustrated, is generally rectangular in shape. Each of thetang members360 is sized to engage atang recess362 in theproximal end56gof thesecond stem structure14g. Engagement of thetang members360 into theirrespective tang recess362 inhibits relative rotation between thesecond stem structure14gand thesecond bearing components18gand18h.
• InFIG. 15,second bearing component18mis shown to have afastener aperture380 which is formed through a bearingmember82mandcage portion80m.Second stem structure14m, which is a threadedfastener382 in this embodiment, is disposed through thefastener aperture380 insecond bearing component18mand threadably engaged to thecancellous bone384 of theulna54m. Construction in this manner is advantageous in that it permits the extent of the trauma experienced by the patient to be minimized. To further this goal, thedistal end386 ofcage portion80mis shown to be generally cylindrically shaped so as to minimize the amount of bone that must be removed to prepare theulna54mfor thesecond bearing component18m.
• InFIGS. 16 through 18, a portion of a modular prosthetic joint kit constructed in accordance with the teachings of a third aspect of the present teachings is generally indicated byreference numeral10n. Modular prostheticjoint kit10nis shown to include abearing insert400, a retainingring402 and asecond stem structure14nhaving an integrally attachedcage portion80n.Cage portion80nis shown to include abearing aperture406 for receivingbearing insert400. In the particular embodiment illustrated,cage portion80nalso includes a circumferentially extendingfirst ring groove408 formed along the perimeter of bearingaperture406 and operable for receiving a first portion of retainingring402.
• Bearing insert400 is generally cylindrically shaped, having a pair ofspherical depressions420 which collectively form a bearing surface that is configured to mate with the spherically-shapedbearing portions66 of thefirst bearing component16.Bearing insert400 also includes a throughhole422 which is adapted to receivepin portion62, preferably without transmitting load therebetween. A circumferentially extendingsecond ring groove424 is formed in the outer perimeter of bearinginsert400, thesecond ring groove424 being operable for receiving a second portion of retainingring402. Construction in this manner is advantageous in that the surgeon may select abearing insert400 from a plurality of bearinginserts400 to adapt prosthetic joint10nto the patient.
• In the particular embodiment illustrated, bearingaperture406 is shown to include a plurality of radially outwardly extendingtab apertures430 and bearinginsert400 is shown to include a plurality of radially outwardly extendingtabs432. If desired, a first one of thetab apertures430 and a first one of thetabs432 may be sized differently than the remainingtab apertures430 andtabs432, respectively, to key thebearing insert400 to a specific orientation relative tosecond stem structure14n.
• With specific reference toFIG. 18, each of the pair ofspherical depressions420 includes a firstspherical portion450 and a secondspherical portion454. Each of the firstspherical portions450 are formed into bearinginsert400 along anaxis456 that is coincident with the longitudinal centerline of thebearing insert400. Each of the firstspherical portions450 are formed by a spherical radius approximately equal in magnitude to the spherical radius which defines the spherically-shapedbearing portion66 of each of thecondyle portions60 offirst bearing component16. The distance between the spherical radii alongaxis456 is equal to a predetermined distance, d.
• Thecenterpoint456 of the spherical radius that defines one of the firstspherical portions450 is employed to generate the secondspherical portion454 on the opposite face of the bearing surface. Asecond centerline468 is constructed fromcenterpoint460 toward the opposite face at apredetermined constraint angle470, such as 3.5 degrees. The spherical radius that defines the secondspherical portion454 on the opposite face is generated from asecond centerpoint472 which is positioned along thesecond centerline468 at a distance d fromcenterpoint460. Construction of bearinginsert400 in this manner permitsfirst bearing component16 to rotate aboutcenterline456, as well as to pivot relative to bearing insert400 about the spherically-shapedbearing portion66 of each of thecondyle portions60.
• Atransition zone480 is formed between each of the first and secondspherical portions450 and454 wherein a radius is formed at the intersection of the radii which define the first and secondspherical portions450 and454 to “soften” the transition between the first and secondspherical portions450 and454 to render the movement of thecondyle portions60 over the first and secondspherical portions450 and454 more comfortable to the patient.
• Those skilled in the art will understand that the degree of the constraint may be defined by the constraint angle. Accordingly, modular prostheticjoint kit10npreferably includes a plurality of bearing inserts400, each having a bearing surface with a secondspherical portion454 that is defined by a different constraint angle. Those skilled in the art will also understand that the degree of the constraint may be additionally or alternatively defined by a constraint characteristic, which is illustrated inFIGS. 19A through 19D.
• InFIG. 19A, bearing insert400ahas a first predetermined constraint characteristic orientation wherein the centerlines which define the radii which define first and secondspherical portions450 and454 are contained in a plane which is generally perpendicular to the longitudinal axis of the ulna. Construction of bearing insert400ain this manner provides a varying degree of axial constraint. InFIG. 19B, bearinginsert400bhas a second predetermined constraint characteristic wherein the centerlines which define the radii which define first and secondspherical portions450 and454 are contained in a plane which is at approximately 45° to the longitudinal axis of the ulna. Construction of bearinginsert400bin this manner provides a varying degree of a combination of axial and varus/valgus constraint. InFIG. 19C, bearinginsert400chas a third predetermined constraint characteristic wherein the centerlines which define the radii which define first and secondspherical portions450 and454 are contained in a plane which is generally parallel the longitudinal axis of the ulna. Construction of bearinginsert400cin this manner provides a varying degree of varus/valgus constraint. InFIG. 19D, bearinginsert400dis constructed in a manner that is generally similar to that of bearinginserts400a,400band400cexcept that the constraint angle employed to construct bearing insert400dis rotated form point x1 to y1 as indicated inFIG. 19d. As a result, there is no single line of orientation in which the constraint is limited. Construction of bearinginsert400din this manner provides a varying degree of constraint in both an axial direction and a varus/valgus direction.
• InFIGS. 20 through 22, a portion of a modular prosthetic joint kit constructed in accordance with the teachings of an alternate embodiment of the third aspect of the present teachings is generally indicated byreference numeral10p. Modular prostheticjoint kit10pis similar to modular prostheticjoint kit10nin that it includes abearing insert400pand asecond stem structure14phaving a integrally attachedcage portion80p.
• Cage portion80pis shown to include abearing aperture406pfor receivingbearing insert400p. In the particular embodiment illustrated,cage portion80pincludes a plurality oftab apertures430p, a plurality oftab slots500 and ahook structure502. Each of thetab apertures430pextends axially throughcage portion80pand circumferentially around a portion of bearingaperture406p. Each of thetab slots500 intersects one of thetab apertures430pand extends circumferentially around a portion of bearingaperture406paway from its associatedtab aperture430p.Hook structure502 is adjacent one of thetab apertures430pand extends radially inwardly and circumferentially around a portion of bearingaperture406p. Aclip slot510 is formed circumferentially throughhook structure502.
• Bearing insert400pis generally similar to bearing insert400 except for the configuration of the plurality oftabs432pand the incorporation of aclip structure520 into abearing body522. Each of the plurality oftabs432pis relatively thin and do not extend axially across bearinginsert400p. This permits thetabs432pof bearinginsert400pto be aligned to atab aperture430pand bearinginsert400pto be rotated so that each of thetabs432pis disposed within one of thetab slots500 to thereby prevent bearing insert400pfrom moving in an axial direction.
• Clip structure520 is preferably a metal or plastic fabrication which is suitable for molding into bearingbody522.Clip structure520 includes anarm structure530 which extends from aclip body532 and terminates at its distal end at ahook member534.Clip structure520 is configured and incorporated into bearingbody522 such when bearinginsert400pis rotated to engagetabs432pintotab slots500,arm structure530 simultaneously engagesclip slot510 inhook structure502. Rotation of bearinginsert400pto a predetermined rotational position relative to hookstructure502permits hook member534 to engage anedge540 ofhook structure502.Arm structure530 resilientlybiases hook member534 againstedge540, thereby inhibiting rotation of bearinginsert400pwhich would causetabs432pto disengagetab slots500.
• InFIG. 20B, bearinginsert400p′ is illustrated to be configured similarly to bearing insert400pexcept that a lockingaperture800 is formed into one of thetabs432p′.Bearing insert400p′ is inserted into bearingaperture406p′ aligned such that each of thetabs432p′ is aligned to an associated one of thetab apertures430p′.Bearing insert400p′ is then rotated so that each of thetabs500′ is disposed within one of thetab slots440p′ and lockingaperture800 is aligned to acorresponding locking aperture802 formed in the integrally attachedcage portion80p′ ofsecond stem structure14p′. Engagement oftabs500′ into theirrespective tab slots440p′ prevents bearinginsert400p′ from moving in an axial direction. Alignment of lockingapertures800 and802 to one another permits apin806 to be inserted therethrough to prevent bearing insert400p′ from rotating relative to integrally attachedcage portion80p′. In the particular embodiment illustrated,pin806 includes ahead portion808, abody portion810 and anend portion812.Head portion808 has a diameter which is larger than the diameter of the hole formed by lockingapertures800 and802.Body portion810 is preferably smaller in diameter than the diameter of the hole formed by lockingapertures800 and802.
• A plurality ofslots814 are formed inend portion812 which creates a plurality offingers816 which are flexible relative to the longitudinal axis ofpin806.Fingers816 flex inwardly toward the longitudinal axis ofpin806 whenpin806 is inserted to lockingapertures800 and802, eliminating the interference therebetween to permit thefingers816 ofend portion812 to pass through integrally attachedcage portion80p′ and bearing insert400p′. Once thefingers816 have passed through integrally attachedcage portion80p′ and bearing insert400p′, they flex outwardly away from the longitudinal axis ofpin806 to inhibit the unintended withdrawal ofpin806 from lockingapertures800 and802. Intended withdrawal ofpin806 from lockingapertures800 and802 may be effected through the flexing offingers816 inwardly toward the longitudinal axis ofpin806.
• Those skilled in the art will understand, however, that thepin806 for linking first andsecond stem structures12 and14p′ may be constructed differently. As shown inFIG. 20C, for example, thepin806′ includes head andend portions808′ and812′ having chamfered abuttingsurfaces808p′ and812p′, respectively. The chamfered abuttingsurfaces808p′ and812p′ can abut the lockingapertures800 and802, similar to thepin806. As illustrated, thepin806 inFIG. 20B includes thehead portion808 that is larger than the lockingapertures800 and802 and theend portion812 that can flex so that it can be smaller than the lockingapertures800 and802 to allow passage of at least a portion of thepin806 through the lockingapertures800,802. One skilled in the art will understand that a locking pin can generally pass through an aperture and be held therein, through some mechanism, to allow for interconnection or locking of the various portions relative to one another. Nevertheless, the chamfered abutting surfaces800p′ and812p′ can allow for a selected engagement of apin806′ between the lockingapertures800,802. Additionally, theend portion812′ includes a chamferedlead portion812p″. The chamferedlead portion812p″ can assist in allowing thepin806′ to be passed through the lockingapertures800,802. Although it will be understood that theend portion808′ can be larger than the lockingapertures800,802 so that the pin can only pass a selected distance through the locking apertures and be held relative to thecage portion80p′ and thebearing insert400p′. As discussed above, in relation to thelocking pin806, theleading end812 can be allowed to pass through the lockingapertures800,802, allowing thelegs816 to flex such that thehead812 passes through the lockingapertures800,802, similar to thehead portion812′ which is configured with the chamferedlead portion812p″ to allow for thepin806 to pass through the lockingaperture800,802. However, theend portion808′ is sized to not pass through the lockingaperture800,802 so that thepin806′ can be held in a selected location.Pin806′ is installed by simply pressing it through thebearing insert400p′.
• InFIGS. 23 and 24, a portion of a modular prosthetic joint kit constructed in accordance with the teachings of a fourth aspect of the present teachings is generally indicated byreference numeral10q. Prostheticjoint kit10qis shown to includefirst stem structure12,second stem structure14,first bearing component16 andsecond bearing component18q.Second bearing component18qis substantially similar tosecond bearing component18 except thatcage portion80qis shown to include acam structure600.Cam structure600 includes alobe member602 that extends radially outwardly and terminates at atip604.Lobe member602 is configured such thattip604 contacts thebase102 ofU-shaped member40 to inhibit further relative rotation between first andsecond stem structures12 and14 when the first andsecond stem structures12 and14 are placed in a position corresponding to the maximum extension of a patient's arm. Configuration ofsecond bearing component18qin this manner is advantageous in that it limits the amount by which a patient may rotate their ulna relative to their humerus to prevent hyperextension of the joint.
• InFIGS. 25 and 26, a portion of a modular prosthetic joint kit constructed in accordance with the teachings of a fifth aspect of the present teachings is generally indicated byreference numeral700. Prostheticjoint kit700 is shown to include afirst stem structure702 and asecond stem structure704.First stem structure702 includes astem member710, the distal end of which is configured to fit within the medullary canal of an ulna. Afirst bearing712 and acoupling structure714 are incorporated into the proximal end offirst stem structure702.First bearing structure712 is generally spherically shaped.Coupling structure714 includes alink member720 and aretainer member722.Link member720 is fixedly coupled tofirst bearing712 at a first end and to retainingstructure722 at a second end withlink member720 extending therebetween along an axis generally coincident the longitudinal axis offirst stem structure702. Retainingstructure722 is illustrated to be spherically shaped with flattened ends.
• Second stem structure704 is shown to include astem member730 with a proximal end that is configured to fit within the medullary canal of a humerus. Asecond bearing structure732 is incorporated into the distal end ofsecond stem structure704.Second bearing structure732 includes a generally sphericalsecond bearing surface740 and a T-shapedcoupling aperture742. Afirst portion744 ofcoupling aperture742 has a width which is larger than the width of retainingstructure722.First portion744 is oriented at a position of maximum flexion. In the particular embodiment illustrated, the position of maximum flexion is illustrated to be about 90° to the longitudinal axis ofsecond stem structure704. However, those skilled in the art will understand that the position of maximum flexion may be tailored in a desired manner and may range as high to an angle of approximately 135° to 150° to the longitudinal axis ofsecond stem structure704, depending on the particular application. Asecond portion746 ofcoupling aperture742 has a width which is slightly larger than that oflink member720.Second portion746 extends circumferentially around a portion ofsecond bearing surface740 in a plane that coincides with the longitudinal axis ofsecond stem structure704. The first andsecond portions744 and746 ofcoupling aperture742 intersect and terminate at spherically shapedcavity750.
• To use prostheticjoint kit700, first andsecond stem structures702 and704 are inserted into the medullary canals of the ulna and humerus, respectively.First stem structure702 is then positioned proximate thefirst portion744 ofcoupling aperture742 and retainingstructure722 is inserted throughfirst portion744 and into spherically shapedcavity750. At this point, first and second bearing surfaces712 and740 are in contact with one another and transmit load therebetween rather than throughcoupling structure714. Coupling of first andsecond stem structures702 and704 is complete whenfirst stem structure702 is rotated intosecond portion746. In this position, first andsecond stem structures702 and704 are linked or constrained since the width of retainingportion722 is larger than the width ofsecond portion746 and thereby prevents the withdrawal offirst stem structure702 fromcoupling aperture742.
• While the prostheticjoint devices10 and10ahave been illustrated as havingmodular flanges20 that are fixedly but removably coupled to thefirst stem structure12, those skilled in the art will understand that the teachings, in its broader aspects, may be constructed somewhat differently. For example, the stem structure and modular flange may be unitarily formed as shown inFIG. 27. In this embodiment, thestem12pis illustrated to be similar to thestem12, but includes a flange structure92phaving aflange member96pand acoupling portion96p′ that couples theflange member96pto thedistal portion32pof thestem12p. Theflange member96pis generally parallel thestem member30pand is employed to compress a bone graft against thestem member30p. Unlike themodular flange20 that was described in detail, above, the flange structure92pmust be fitted over abone graft110 or the bone graft must be placed into theaperture800 between thestem member30p.
• Another example of an integrally formed (i.e., non-removable) flange structure is illustrated inFIGS. 28 and 29. In this example, thestem12qis illustrated to be similar to thestem12pin that it includes aflange structure92qhaving aflange member96qand acoupling portion96q′ that couples theflange member96qto thedistal portion32qof thestem12q. Theflange member96q, however, is arcuately shaped and includes acontact tab804. Theflange structure92qis formed with a predetermined degree of resiliency, which may result from the characteristics of the material from which theflange structure92qis formed or by controlling the geometry (i.e., cross-sectional shape and area) of theflange structure92q. The resiliency of theflange structure92qpermits theflange member96qto act as a leaf spring that biases thecontact tab804 toward thestem member30q. Accordingly, the flange may be employed to apply compression to thebone graft110qwithout fasteners or other securing means. As illustrated inFIG. 30, those skilled in the art will readily understand, however, that a predetermined amount of resiliency may also be incorporated into aflange structure92rthat is fixedly but removably coupled to thestem12r.
• Those skilled in the art will also understand that although themodular flange20 has been illustrated as being coupled to thestem12rvia a threadedfastener94b, the teachings, in its broader aspects, may be constructed somewhat differently. For example,cables810 are employed to fixedly but removably retain theflange structure92sto thestem12sas illustrated in FIGS.31 and32. Thestem12sis generally similar to thestem12, but includes afirst coupling feature812 instead of thebore100. Theflange structure92sincludes aflange member96sand acoupling portion96s′. Thecoupling portion96s′ includes asecond coupling feature814 that is configured to cooperate with thefirst coupling feature812 to locate theflange member96srelative to thedistal portion32sof thestem12s. In the example illustrated, thefirst coupling feature812 is a generallytrapezoidal dovetail member816 that extends outwardly from thedistal portion32sof thestem12sand thesecond coupling feature814 is adovetail aperture818 that is formed into thecoupling portion96s′ and sized to engage thedovetail member816 in with a line-to-line fit (i.e., with very little or no clearance). Thedovetail member816 is preferably integrally formed onto thestem12sbut may alternatively be an independently formed component that is fixedly coupled to thedistal portion32svia an appropriate coupling means, such as threaded fasteners, press-fitting or shrink fitting.
• Theflange member96sis shown to include a plurality ofcross-holes820 that extend completely through theflange member96sin a direction that is generally perpendicular the longitudinal axis of theflange member96s. The cross-holes820 are sized to receive thecable810. As those skilled in the art will understand, thecables810 are first secured around thehumerus38sand the ends of thecables810 are loosely secured via an appropriate coupling device, such as acable sleeve822. Thecables810 are then tensioned to urge theflange member96sagainst thehumerus38sand compress thebone graft110sby a predetermined amount. Thereafter, the coupling device is employed to fix the ends of the cables relative to one another so as to maintain tension in thecables810.
• While the first and second coupling features812 and814 have been illustrated as being adovetail member816 and adovetail aperture818, respectively, those skilled in the art will appreciate that the first and second coupling features812 and814 can be constructed somewhat differently. As illustrated inFIG. 33, for example, thefirst coupling feature812tis illustrated as being a pair ofpins830 that are fixedly coupled to thedistal portion32tof thestem12tand the second coupling feature814tis illustrated to be a corresponding pair ofholes832 that are formed into thecoupling portion96t. Thepins830 are preferably press-fit or shrunk fit into corresponding holes (not specifically shown) that are formed into thedistal portion32tof thestem12tbut may be secured via other fastening means, such as welding, bonding, or threaded engagement where thepins830 have a threaded portion that is threadably engaged to the holes in thedistal portion32t. Alternatively, thepins830 may also be integrally formed as a part of thestem12t.
• Another example is illustrated inFIGS. 34 and 35, where thefirst coupling feature812uis shown to include a mountingstructure840 with anarcuate mounting aperture842 and thesecond coupling feature814uis shown to include anattachment hook846. The mountingstructure840 is coupled to thedistal portion32uof thestem12uand extends generally perpendicularly outwardly from the base102uof theU-shaped portion40u. The mountingaperture842 is generally J-shaped and includes afirst portion850, which is aligned generally perpendicular to the base102u, and an arcuatesecond portion852, which extends away from thestem member34uand the base102u. Theattachment hook846 is also generally J-shaped, being configured to matingly engage the mountingaperture842. In this regard, theattachment hook846 includes aleg portion856 that extends downwardly from theflange member96uand anarcuate base member858.
• In coupling the first and second coupling features812uand814u,flange structure92uis initially positioned relative to thestem12usuch that thebase member858 is disposed within thefirst portion850 of the mountingaperture842. Theflange structure92uis then rotated downwardly toward thestem member34uto permit thebase member858 to engage thesecond portion852 of the mountingaperture842. Thecables810 are thereafter employed to fix theflange structure92urelative to thestem12u.
• With initial reference toFIG. 1 and further reference toFIG. 36, a modularjoint prosthesis1000 is illustrated. It will be understood that the illustratedmodular prosthesis1000 illustrated inFIG. 36 can be similar to theprosthesis10 illustrated inFIG. 1, though differences can be provided and discussed herein. Nevertheless, like features and portions will be indicated with like reference numerals and not described again in detail. Briefly, however, as discussed above, themodular prosthesis1000 can be used as a linked elbow prosthesis, although it will be understood according to various embodiments that an unlinked or free elbow prosthesis can be provided, as discussed herein. Theprosthesis1000 can generally include thefirst stem structure12, thesecond stem structure14, afirst bearing component1002, thesecond bearing component18, and various other portions that can be provided or included in themodular prosthesis1000 if selected. It will be understood that all or various portions are discussed above as included in various embodiments. However, not each of the portions are necessarily provided for each of the embodiments if so selected.
• Thefirst bearing component1002 can define afirst condyle portion1004 and asecond condyle portion1006. Thecondyle portions1004,1006, can be similar to thecondyle portions60 illustrated and described above. According to various embodiments, each of thecondyle portions60 can include substantially similar spherical radii. Although thecondyle portion60 need not define a complete sphere, a portion of the sphere, which they can define, can include or define a spherical radius. According to various embodiments, however, thefirst condylar portion1004 can have a firstspherical radius1008 while thesecond condylar portion1006 can include a secondspherical radius1010. The firstspherical radius1008 can be different than the secondspherical radius1010.
• The spherical radii can be any appropriate dimension such as 1 mm to about 3 cm, such as about 0.6 cm to about 2.0 cm. It will be understood, however, that thespherical radii1008,1010, can be any appropriate dimension. For example, thespherical radii1008,1010 can be selected for various purposes, such as to substantially mimic a specific anatomy, and as such the various ranges described herein are merely exemplary. Further, it will be understood that thedimensions1008,1010, which can include spherical radii, can be any appropriate dimensions. For example, it will be understood that thecondylar portions1004,1006 need not specifically define a portion of the sphere, a portion of a cylinder, or the like. Thecondylar portions1004,1006 can be irregular such that they are not a regular shape or surface. The design of thecondylar portions1004,1006 can be specific to various individuals and anatomies, thus not requiring a regular shape.
• Thecondylar portions1004,1006 can include the various portions as discussed above. For example, thecondylar portions1004,1006 can define the bearingportion66 which can be regular or irregular, as discussed above. Further, each can define the slottedapertures68 or other appropriate connection portions, to interconnect with thedistal portion32, such as thelegs42 of thefirst end portion12. It will be understood that theU-shaped portion40, which includes the spaced apart thelegs42, can also be referred to as a yoke or other appropriate portion. Further, each of thecondyle portions1004,1006 can define thepin aperture70 to interconnect with thecondylar pin portion62 to interconnect thecondylar portions1004,1006 in a selected manner. As discussed above, however, thecondylar portions1004,1006, can be substantially formed as a single member or portion that can include thecondylar pin62aas a single portion with thecondylar portions1004,1006.
• Further, as discussed above, thecondylar portions1004,1006, the condylar pins62, and any other portions of theprosthesis1000 can be formed of various materials. For example, it can be selected to form thecondylar portions1004,1006 from a single material, a composite material, or the like. For example, thecondylar portions1004,1006 can define the bearing surfaces66 formed of a polymer material, such as a high molecular weight polyethylene. Thesecond bearing member18 can also be made of similar materials. Nevertheless, they can also be formed with a metal, metal alloy, ceramic, or the like to achieve various results.
• Further, it will be understood that thesecond bearing portion18 can include various features and be formed of various materials, including those discussed above. Thesecond bearing member18 can include the bearingcage80, thesecond bearing cage80awhich defines theslot150, or the substantially unconstrained or unlinked various embodiments that include the bearingmember82′ and the features thereof as discussed above. Therefore, it will be understood that thecondylar portions1004,1006 can be interconnected with any appropriatesecond bearing portion18,18′ including those described above.
• Further, theprosthesis assembly1000 can include various portions that allow for the substantial non-linear alignment of thecondylar portions1004,1006 relative to one another. It can be selected to non-align or offset afirst center1012 of thefirst condylar portion1004 and asecond center1014 of thesecond condylar portion1006. It will be understood that thecenters1012,1014, can be any operative center or portion of the prosthesis according to various embodiments and defining a geometrical center is merely exemplary. The centers can be offset in various manners such as an anterior-posterior non-alignment, a superior-inferior non-alignment, or combinations thereof.
• For example, an anterior-posterior spacer kit can include afirst spacer1016, asecond spacer1018, and athird spacer1020. Each of the spacers1016-1020 can include adimension1016′-1020′ respectively. Thedimensions1016′-1020′ can move or displace the selectedcondylar portions1004,1006 relative to the other. A selected spacer, such as thespacer1016, can be positioned in theslot68 such that a passage1022 through thespacer1016 aligns with thepassage72 through thecondylar portion1006 so that when theleg42 is positioned within theslot68, theleg42 is unaligned with thefirst condylar portion1004. A substantially alignedaxis1024 can pass through the twocenters1012,1014 of therespective condylar portions1004,1006 and through thecondylar pin62. Nevertheless, thespacer1016 can offset a selected condylar portion, such as thesecond condylar portion1006 relative to thefirst condylar portion1004. Therefore, an offsetangle1026 can be formed between thefirst condylar portion1004 and thesecond condylar portion1006.
• In various configurations, such as an unaligned configuration, various portions are optional. For example, thepin62 is optional in various configurations. As discussed above, the bearingmembers1002 and1006 bear the force and the pin can assist with strength and stability of the assembly. Thus is thepin62 can be omitted between the condyles.
• The offset angle ordistance1026 can be any appropriate dimension. The appropriate dimension can be selected for various purposes, such as the specific anatomy of the patient, a selected result, or the like. For example, the offset angle can be about 1° to about 20°, such as about 3° to about 10°. Nevertheless, the offset angle can be any appropriate angle depending upon a selected condition. The offsetangle1026 can be altered by choosing a different one of the spacers1016-1020 and can be selected pre-operatively, intra-operatively, or at any appropriate time.
• Each of the spacers1016-1020 can include a passage oropening1016a-1020a. The opening can be a round bore, elongated, a slot or any appropriate opening. Theopenings1016a-1020acan be provided to align or be oriented with theopenings72 in the first andsecond bearing members1002 or1006 and a selectedpassage1016a-1020a.
• Theopenings72 can also be circular, oblong, slotted, or formed in any appropriate shape or manner. The interaction of theopening72 in thebearing members1002 and1006 and with theopenings1016a-1020ain the spacers1016-1020 can help ensure an appropriate fit of theprosthesis1000.
• A second set of spacers1030-1034 can also be provided. The spacers1030-1034 can each include adimension1030′-1034′ respectively. Therespective dimension1030′-1032′ can be any appropriate dimension and allow for a selected superior inferior offset. A selected spacer, such as thespacer1030, can be positioned in theslot68 to offset thesecond condylar portion1006 relative to thefirst condylar portion1004. The offset amount can be similar to theangle1026 except in a different dimension or orientation. The spaces1030-1034 can also includepassages1030a-1034a, respectively, that can be similar to thepassages1016a-1020a. Thepassages1030a-1034acan be round, slotted, oblong, etc. They can be provided to allow for a selected orientation of theprosthesis1000.
• It will be understood, however, that any appropriate number of the various spacers such as the spacers1016-1020 and the spacers1030-1034 can be provided for any appropriate purpose. For example, a plurality of the spacers1016-1020 and1030-1034 can be provided in minute and discreet differences to allow for an intra-operative selection of a selected offset or to allow for a plurality of offsets for creation from a set of instruments and portions.
• With continuing reference toFIG. 36, a third set ofspacers1017,1019,1021 can be provided. Although the discussion herein includes a discussion related to three sets of spacers, it will be understood that a set of spacers can include any of the appropriate spacers, all of the spacers, or a selected portion thereof depending upon selected purposes. Nevertheless, the third set of spacers, called that for simplicity of the present discussion, can be formed dissimilar to the second set of spacers1030-1034. Nevertheless, the third set of spacers1017-1021 can include afirst side1017a-1021athat has a dimension that is the same or different than a second side1017b-1021b. The various sides can include any appropriate dimension, however, the dimension of side1017b-1021bcan be varied for various purposes, such as a reason similar to varying the dimension of the first spacer sets1016-1020. The side1017b-1021bcan include adimension1017′-1021′ that can be selected for any appropriate purpose, such as a selected offset, including an anterior or posterior offset. The offsets can be any appropriate offsets, and can be similar to, different, or complementary to the offsets of the spacers1016-1020. Further, the third set of spacers1017-1021 can include a third side1017c-1021c. It will be understood that the various sides can be any appropriate portions of the spacers1017-1021 and has described the sides merely for the discussion herein. Nevertheless, the third side,1017c-1021ccan also include avariable dimension1017″-1021″. Thedimension1017″-1021″ can include any appropriate dimension, such as dimensions similar to the dimensions of the second spacer sets1030-1034.
• Therefore the third spacer set1017-1021 can include a variable dimension of more than one side or portion of the spacers1017-1021 for various purposes. For example, it can be selected to provide the spacers1017-1021 to include a selected offset in more than one direction or orientation relative to theprosthesis1000 or an anatomy into which it is positioned. Therefore, the spacers1017-1021 can be used to achieve an appropriate orientation of theprosthesis1000 in a single member. Nevertheless, it will be understood that a modular spacer assembly can be provided to achieve a selected offset in theprosthesis1000. Having a spacer member that is formed as a single portion or body is not necessary and a modular spacer system can be provided. Nevertheless, a single spacer can include an offset in various dimensions, as exemplary illustrated in the spacers1017-1021.
• Further, the spacers1017-1021 can include a passage1017d-1021dsimilar to the passages described above in the various spacer systems. The passage1017d-1021dcan be circular, oblong, slotted, or any appropriate orientation, size, or the like. The select passage1017d-1021dcan be provided to interact with thepassages72 and thebearing members1002 and1006 to achieve a selected orientation of the spacer members relative to thebearing members10021006.
• With reference toFIG. 37 and continuing reference toFIG. 36, the detailed cross-sectional view of thecondylar portions1004,1006 relative to thesecond bearing member18 is illustrated in an assembled manner. As illustrated inFIG. 37, a selected one of the spacers, such as thespacer1030 can be inserted into theslot68 to displace thesecond condylar portion1006 relative to thefirst condylar portion1004. Therefore, theangle1026 is formed between thefirst center1012 and thesecond center1014 with thecondylar portions1004,1006. Further, as illustrated inFIG. 37, thesecond condylar portion1006 can include thedimension1010 that is larger than thedimension1008 of thefirst condylar portion1004. Thus, thecondylar portion1006 can be designed to mimic a selected portion of the anatomy, if so selected.
• Nevertheless, it is still understood that the bearing surfaces66 can bear on the bearingmember84 of thesecond bearing member18 in an appropriate manner. Thus, thecondylar pin62 does not or is not required for proper articulation and may not engage a selected portion of the bearingmember84 after positioning or implantation of theprosthesis1000. For similar reasons, thepin62 is not required in the assembly as discussed above. Thepin62 can be omitted for various reasons, such as ease of assembly. Although one skilled in the art will understand that thepin62 can be used for various reasons, including stability, strength, alignment, and the like. Also, the selected anatomical geometry can be obtained with theprosthesis1000, which can use any or a plurality of the spacers1016-1020,1030-1034, or1017-1021 to achieve any appropriate offset or angle and also the dimension of thecondylar portions1004,1006 can be selected to achieve the appropriate results.
• With reference toFIG. 38, amodular prosthesis assembly1060 can include various portions, including those discussed above. It will be understood that the similar portions can be referenced by like numerals and a detailed description thereof need not be necessary here to understand the various embodiments. Nevertheless, thefirst stem assembly12 can be provided to interconnect with afirst bearing assembly1062 and asecond stem assembly14 and athird stem assembly220. As discussed above, thefourth bearing component222 can be provided with thestem assembly220 to interconnect with the radius to replace articulating portion thereof. It will be understood that thestem assembly220 can be provided with various portions to achieve a replacement of a selected portion of the radius.
• It will be further understood that, as described above in various embodiments, that the bearingportion222 can be formed as a single member with thesecond stem assembly14 according to various embodiments. Thefirst bearing assembly1062 can include afirst condylar portion1064, asecond condylar portion1066 and theextension240. Theextension240 can be provided to extend from a selected portion of thefirst bearing member1062 such as medial or laterally from thefirst bearing member1062. Theextension240 can define theextension bearing member242 that can articulate with the bearingportion222 of thestem220 or with the natural portion of the radius. Further, as discussed above, the bearingsurface222 can articulate with the natural portion of the humerus if so selected. Also, thesecond bearing member18 can be provided in a substantially linked, unlinked or unconstrained, semi-constrained or linked, or a slot that allows access to thebore86 in any appropriate manner.
• Thefirst bearing member1062 can be interconnected with thefirst stem member12 in any appropriate manner, including the various screws or fixingmember64 as described above. Further, thecondylar portions1064,1066 can be interconnected with thecondylar pin62cin any appropriate manner, including those discussed above. Nevertheless, thefirst condylar member1064 can be provided in a different manner, geometry, size, etc., than asecond condylar member1066.
• As discussed above, thefirst condylar member1064 can have a centerpoint1068 that can define a center of a sphere or any other regular or irregular shape. For example, thefirst condylar portion1064 can define aspherical radius1070 that extends from thecenter1068 to an edge of thecondylar member1064. Thesecond condylar member1066 can also define acenter1072, which can be the center of a sphere or any other appropriate shape or irregular shape. Further, the second condylar portion can define a secondspherical radius1074. As discussed above, thespherical radii1070,1074 can be provided to be equal, different, or in any appropriate combination. Nevertheless, it will be understood that thecondylar portions1064,1066 can include a different dimension and be interconnected with the various portions, such as theextension242 to articulate with various portions of the anatomy or prostheses positioned therein. It will also be understood that thecondylar portions1064,1066 can interconnect with thefirst stem member12 in any appropriate manner. Therefore, various further portions, such as the spacers1016-1020,1030-1034, or1017-2021 can be provided with theprosthesis system1060.
• It will be understood that the various embodiments of the prostheses, whether linked or unlinked or constrained or unconstrained can be provided in various portions of the anatomy. Nevertheless, the exemplary elbow prostheses can be provided in various manners for selection by a user. As discussed above, a kit can include each and every of the various portions of the various embodiments for selection by a user during an operative procedure, prior to an operative procedure, or at any appropriate time. Therefore, the modular prosthesis, according to various embodiments, can be provided for use by a user in a selected manner to achieve a selected result.
• Further, with exemplary reference toFIG. 39, theprosthesis1000 can be positioned in the anatomy in any appropriate manner. The modular prosthesis can be provided to be positioned relative to various portions of the anatomy, such as a humerus, a radius, an ulna, or any appropriate portions through a selectedincision1200 relative to theelbow1202 joint between thehummers1204 andulna1206. It will be understood that the modular nature of theprosthesis1000, can be provided for a procedure that can be performed through a relatively minor incision that need not be larger than various portions of the modular prosthesis. This can achieve various results, such as minimizing recovery time, minimizing operation time, or various selected results. Further, as discussed above, the modular nature of the various portions and various embodiments can provide for achieving a selected revision procedure. For example, having the various sizes of the condylar portions, which can include different dimensions, a revision procedure can be provided to maintain or augment a selected result to achieve a more anatomical result in a selected period. Further, the prosthesis, according to various embodiments, can be changed from a constrained to unconstrained or from an unconstrained to a constrained. The change can be provided during a selected procedure, such as a revision procedure to account for changes in the anatomy over time. Nevertheless, the modular prosthesis according to various embodiments can be provided for selection by a user to achieve a more natural anatomical result after implantation of the prosthesis.
• With reference toFIG. 40, a humeral prosthesis stem assembly orstructure1300 is illustrated. Thestem assembly1300 can include a first andsecond arm1302,1304 to cooperate or engage the pair ofcondyle portions60, according to various embodiments. Thestem assembly1300 can include astem portion1306 that is operable to extend into a canal, such as the intramedullary canal of a humorous. Extending with thehumeral stem assembly1300 can be a flange attachment orconnection member1310. Theflange attachment member1310 can define a dovetail, such as amale dovetail1312. Theflange attachment member1310 includes a bore orpassage1314.
• Amodular flange member1320 can interconnect with theflange attachment member1310. Themodular flange member1320 can define afemale dovetail connection1322. Themodular flange member1320 can also include a passage or bore1324 through which a locking screw or setscrew1326 can pass. During or with an implantation procedure, themodular flange member1320 can slide over theflange attachment member1310 and theset screw1326 can lock themodular flange member1320 to theflange attachment member1310.
• It will be understood, according to various embodiments, that themodular flange member1320 includes a female or male connection portion other than the dovetailfemale dovetail connection1322. Theflange attachment member1310, however, can include any appropriate connection portion other than themale dovetail1312. The appropriate connection portion allows theflange member1320 to be slid axially over theflange attachment member1310. By axially sliding or moving the flange member to connect it to theflange attachment member1310 increased resistance to rotation or torsion can be achieved of the flange member relative to the remainder of thestem assembly1300. As discussed above, theflange member1320 can be provided to resist rotation of thestem assembly1300 in the anatomy.
• For example, the male and female dovetails can be reversed or other appropriate configurations can be provided. For example, a male T-portion and a female T-portion can be provided on the respectiveflange attachment member1310 andmodular flange members1320. The T-portions can also allow an appropriate cooperation of theflange member1320 and theflange attachment member1310.
• Theflange member1320 can be provided with anyappropriate length1320L. Thelength1320L can also be provided to vary amongst a plurality of theflange members1320. The plurality of theflange members1320 can be provided in a kit, such as in theprosthesis assembly1000 illustrated inFIG. 36 or any other appropriate kit or modular prosthesis assembly.
• As discussed above, theflange member1320 or theflange attachment member1310 can be provided to engage the humerus to assist in reducing or eliminating rotation of thehumeral assembly1300 after or during implantation. Themodular flange member1320 that can be provided in a plurality of lengths and the appropriate length can be selected by a user, such as the surgeon, during a procedure. The length of themodular flange member1320 can be selected based upon the length of the patient's humerus, the amount of area to be covered to resist rotation, and for other selected purposes.
• Themodular flange member1320 can also be interconnected with theflange attachment member1310 at any appropriate time. For example, theflange member1320 can be interconnected with theflange attachment member1310 prior to positioning thehumeral stem assembly1300 into a humerus of the patient. Alternatively, theflange member1320 can be interconnected with theflange attachment member1310 after positioning thestem portion1306 within the humerus.
• According to various embodiments, a multiple or plural flangehumeral assembly1330 can be provided, as illustrated inFIG. 41. Thehumeral assembly1330 can include two arms or furcations1332 and1334 to engage the condyle bearings, as discussed above. Thehumeral assembly1330 can further include a stem portion1336 to engage or be positioned in the humerus, as also discussed above. A modular flange assembly1340 with multiple members are assembled to engage the stem portion1336 cooperate with the stem portion1336. The modular flange assembly1340 can include any appropriate number of modular members, including two as discussed herein. Also, the modular flange assembly can connect directly to thestem portion1306 or any appropriate portion of thehumeral assembly1330, including near the two arms orfurcations1332,1334. The modular flange assembly1340 can allow for greater flexibility during a procedure and multiple sets of the modular flange assembly1340 can further increase flexibility.
• Aflange connection member1342 can include a connection portion1344 to connect with anarcuate mounting aperture842. Thearcuate mounting aperture842 can be provided to interconnect with the connection portion1344 as discussed above. Thearcuate connection aperture842 and the connection portion1344 can allow for a selected connection of theflange connection member1342 to the remainder of thehumeral assembly1330.
• In addition, theflange connection member1342 can include a threaded bore orpassage1346 similar to thepassage1314 discussed inFIG. 40. In addition, theflange connection member1342 includes a maledovetail connection portion1348. A separatemodular flange member1352 includes alength1352L. Themodular flange member1352 includes a femaledovetail connection region1354 to cooperate with themale dovetail1348. As discussed above, however, a dovetail connection is not required and any appropriate selectable connection can be provided.
• Apassage1356 if formed through theflange member1352. A locking or setscrew1358 can pass through thepassage1356 and thepassage1346 to assist in locking or holding theflange member1352 to theflange connection member1342. Theflange member1352 can be held or fixed relative to theflange connection member1342 with any appropriate mechanism, such as a tab or deflectable finger.
• As discussed above, theflange member1352 can be provided in any appropriate length. Further, thelength1352L can vary among a plurality of theflange members1352. A plurality of theflange members1352 can be provided in a kit or in a modular assembly system, such as themodular assembly system1000. The user can select the appropriatelength flange member1352 for any appropriate reason, such as that discussed above.
• In addition, the kit, or any appropriate kit, can include a humeral assembly portion, such as thehumeral assembly1300 or thehumeral assembly1330. A selection of an appropriate humeral assembly can be made for appropriate purposes, such as providing for a selected or unique anatomy of a patient. For example, if a patient's anatomy is substantially planar theflange attachment member1310 can be used.
• If varying widths of a patient's anatomy need to be accommodated then the multiple modular flange assembly1340 can be used to accommodate the varying widths with a plurality of members. For example, the arcuate connection1344 can position theflange connection member1342 at any selected distance from the stem portion1336. Theflange member1352 can then be selectively interconnected with theflange connection member1342 during an implantation procedure.
• It will be understood that the flange assembly1340, theflange member1320, or a flange according to the various embodiments can be provided with any appropriate humeral assembly. The humeral assembly can be implanted for forming a portion of an elbow joint, as discussed above. The flange assembly can be provided with a modular member to select a selected length, offset, or other configuration of the flange member relative to the stem portion of the humeral assembly.
• As discussed above, a prosthetic joint10 can include abearing component16 that includes first andsecond condyle portions60. As further discussed above, and illustrated inFIG. 1, the condyle portions can be connected to thefirst stem structure12 with afastener64. Thefastener64 can pass through bores or passages in thecondyle portions60 and in thestem structure12 to connect thecondyle portions60 to thestem structure12. According to various embodiments, as illustrated inFIGS. 42-44, a first andsecond stem structures12,14 and thebearing component16 can be associated to form an elbow joint prosthesis.
• For example, afastener64′ can be provided and positioned to interconnect thecondyle portions60 with the arms orfurcations42. Thefastener64 can extend through thefurcation42 and engage thecondyle portion60 to hold the condyle portion relative to therespective furcation42. Similarly, thefastener64′ can pass through or engage both thecondyle portion60 and therespective furcation42 to hold thecondyle portion60 relative to therespective furcation42. Thefastener64′ can include a first and a second fixation or fastening region. As discussed herein, first and second fastening regions can include first andsecond fastener grooves1370,1372 and afastener thread1374.
• Thefastener64′ includes ahead1364, ashaft1366 extending from the head, and a distal tip orregion1368. Thefastener64′ further includes afirst fastener groove1370 and asecond fastener groove1372. Theshaft1366 includes amale fastener thread1374 located intermediate thehead1364 and thedistal tip1368 in the depicted embodiment. Thefastener thread1374 can be provided to engage a female thread, such as afemale thread1376 of the threadedfastener aperture44. Thefastener64′ also passes through at least one part of the mountingaperture72 in thecondyle portion60.
• During an assembly, thefastener64′ can pass through a first part of the mountingaperture72, pass through the threadedfastener aperture44, and pass through a second part of the mountingaperture72. It will be understood that thefastener64′ need only pass through a one part of the mountingaperture72. Thefastener64′ can be held at a selected location relative to thefurcation42 and thecondyle portion60 at least with thefastener threads1374 in the threadedfastener aperture44.
• The threaded interaction between thefastener threads1374 and thefemale threads1376 can create or generate a first fastening interaction. A second fastening interaction can be formed with a second fastener and by either or both of thegrooves1370 and1372 in thefastener64′ and cooperatinggrooves1380 and1382 included in the mountingaperture72. A groove can also be defined in the threadedfastener aperture42. The second fastener can be at least one of afirst locking spring1386 and asecond locking spring1388. Thesprings1386,1388 can be any appropriate springs, such as helical spring or flex spring members. The second fastener can also be a locking ring or C-ring1390. The second fastener is provided to cooperate with one of the selectedgroove pairs1370 and1380 or1372 and1382. The locking springs1386,1388 can be positioned between the pairs ofgrooves1370,1380 or1372,1382 to resist movement of thefastener64′ within any of the threadedfastener aperture44 or mountingaperture72.
• As best illustrated inFIG. 44, thefastener64′ can be positioned within therespective apertures72,44, and thesprings1386,1388 can be positioned within the groove pairs1370,1380 or1372,1382 to assist in holding thefasteners64′ within the apertures. At least one of thesprings1386,1388 is placed in thegrooves1380,1382 of thecondyle portions60 or any appropriate portion of the assembly during assembly. Thefastener64′ is inserted to engage at least one of thesprings1386,1388 which flexes thespring1386,1388. Thefastener64′ is then further inserted to allow thespring1386,1388 to relax into therespective fastener groove1370,1372
• The second fastener is provided to assist in resisting movement of thefastener64′. For example, once thefastener64′ is positioned in theprosthesis10 and multiple articulations or cycles of theprosthesis10 occurs within a patient, thefastener64′ may loosen relative to thefurcation42. Thelocking spring1386,1388 or any appropriate locking member can ensure that thefastener64′ does not move more than a selected distance. Accordingly, thecondyle member60 can be maintained connected to therespective furcations42.
• Thefirst bearing component16, according to various embodiments, can be held in place relative to thefirst stem structure12, as discussed above. It can be selected to provide both a first and second interaction for thefastener64′. Thefirst bearing component16 can then be implanted or positioned to articulate with thesecond bearing component18.
• With reference toFIGS. 45-47B, asecond stem structure1400 having asecond bearing component1402 can include a cage orenclosed structure1403 that can couple with or hold abearing member1404 in a selected position in asecond stem structure1400. The bearingmember1404 can define abearing surface1406 that can include two faces or opposing partially- or semi-spherical bearing surfaces. A through bore orpassage1407 can also be defined through the bearingmember1404. The bearing surfaces1406 andpassage1407 can have any appropriate configuration, including that discussed above. For example, thebearing surface1406 can include two bearing sections defined around axes that are at an angle relative to one another. The various configurations of the bearing structure of the bearingmember1404 are discussed above and not repeated here.
• The bearingmember1404 can be held within thecage1403 with a holding member, such as tabs1410a-1410cincluded in anexterior surface1411 of the bearingmember1404. The holding member can include portions of both the bearingmember1404, thecage1403, or other members, as discussed herein. The tabs1410a-1410ccan extend aheight1412 above theexterior surface1411 of the bearingmember1404. The tabs1410a-1410ccan pass through tab entries1420a-1420cin thecage1403 formed in asidewall1422 of thecage1403. Although three tabs1410a-1410care discussed and illustrated here, any appropriate number of tabs can be provided.
• Grooves or depressions1426a-1426care defined within an interior surface or below aninterior surface1428 of thecage1403. The groove1426a-1426ccan engage or cooperate with the tabs1410a-1410c, as illustrated inFIG. 47A. The tabs1410a-1410ccan be made to engage or cooperate with the grooves1426a-1426cby moving the bearingmember1404 into thecage1403 by positioning or aligning thetabs1410awith the tab entries1420a-1420c. The bearingmember1404 can then be rotated in a selected direction, such as the direction indicated byarrow1429 inFIG. 46, to move the tabs1410a-1410cwithin the grooves1426a-1426c. The direction that the bearingmember1404 is moved can be any appropriate direction, and the direction ofarrow1429 is merely exemplary. The bearingmember1404 is inserted into thecage1403 in an insertion position and is rotated to an implanted or fixed position.
• Once the bearingmember1404 is rotated to a selected or locked position relative to thecage1403, a locking or setscrew1432 can be positioned in thesecond stem structure1400 to fix or hold the bearingmember1404 in the implanted position. Theset screw1432 can pass through or cooperate with astem passage1434 to engage or cooperate with aset region1436 of the bearingmember1404. Theset region1436 can include a cam or other appropriate surface to be engaged or contacted by theset screw1432.
• Theset screw1432 can be positioned to resist rotation of the bearingmember1404. In other words, the set screw can stop the bearingmember1404 from returning to the insertion position, which is contrary to the direction of thearrow1429. Therefore, the bearingmember1404 can be held within thecage1403 by the tabs1410a-1410ccooperating with the respective grooves1426a-1426cof thecage1403.
• The bearingmember1404, therefore, can be a substantially modular bearing member that is selected for appropriate materials, configurations, sizes, and the like during an implantation procedure. For example, as discussed above, the bearingsurfaces1406 can include a multiple and angled bearing surface portions. A plurality of bearingmembers1404 can be provided to include a plurality of angles between respective central axes of the bearing surfaces defining thebearing surface1406. The user can select the bearingmember1404 prior to or during a procedure based upon the patient's anatomy. Various other purposes for providingmodular bearing members1404 can also be provided and are discussed above.
• With reference toFIGS. 48-50B, asecond stem assembly1500, according to various embodiments, is illustrated. Thesecond stem structure1500 includes asecond bearing component1502 that includes acage1504 in abearing member1506. The bearingmember1506 can be similar to the bearingmember1404, discussed above, including a bearing surface having multiple bearingsurface configurations1508 and apassage1510. The bearingmember1506, however, can differ from the bearingmember1404 at least in that bearingmember1506 includes one or a plurality of grooves1518a-1518bthat are part of a holding member or mechanism. The grooves1518a-1518bcan be defined below a surface or defined to extend from anexterior surface1520 of the bearingmember1506. The bearingmember1506 can also include tab entry regions1522a-1522balso defined relative to theexterior surface1520 of the bearingmember1506.
• Thecage1504 of thesecond bearing component1502 can also be similar to thecage1403 discussed above. Thecage1504 can include aninterior surface1530 with one or a plurality oftabs1532aand1532bthat also form part of the holding member or mechanism. The bearingmember1506 is positioned within thecage1504 by moving thetabs1532aand1532binto thetab entry grooves1522aand1522b.
• Once the bearingmember1506 is within thecage1504, the bearingmember1506 can be rotated in the direction ofarrow1536 illustrated inFIG. 49, resulting in the tabs1532a-1532bbeing positioned within the locking or holdinggrooves1518aand1518b, as illustrated inFIGS. 50A and 50B. The bearingmember1506 is inserted into thecage1504 in an insertion position and then rotated to an implanted or fixed position.
• Once the bearingmember1506 is rotated to the selected lock or implanted position, a locking or setscrew1540 can be passed through a passage oropening1542 to hold or resist the bearingmember1506 from rotating in a direction contrary to thearrow1536. As discussed and illustrated above inFIG. 47B, theset screw1432 of thesecond bearing component1402 can resist rotation of the bearingmember1404 and assist in holding the bearingmember1404 relative to thecage1403. Similarly, theset screw1540 can hold the bearingmember1506 in the selected or implanted position relative to thecage1504. The bearingmember1506 can then be held within thecage1504 by the interaction of thetabs1532aand1532bwith thegrooves1518aand1518b. Further, in the depicted embodiment, the locking or setscrew1540 can engagesurface1544 to prevent rotation of the bearingmember1506. The locking or set screws, according to various embodiments, can be part of the holding or locking mechanism of the second bearing.
• As discussed above, thesecond stem structure1500 can be an ulnar stem structure. The bearing surfaces1508 of the bearingmember1506 can define opposed dual spherical, semi-spherical or partially spherical bearing surfaces. In addition, each of the opposing faces can define a plurality of bearing surfaces that include angled central axes, as discussed above. Accordingly, thesecond bearing component1502 can be provided as an ulnar bearing for an elbow prosthesis.
• With reference toFIGS. 51-52B, asecond stem structure1600 is illustrated. Thesecond stem structure1600 can be provided as an ulnar prosthesis. Thesecond stem structure1600 includes asecond bearing component1602 including acage1604 interconnected with or affixed to thedistal stem portion1606.
• Thesecond bearing components1602 can further include a bearingmember1610 including selected portions, similar to the portions of the bearingmember1404 discussed above. Generally, the bearingmember1610 can include abearing surface1612 or a plurality of bearing surfaces, such as opposed at least partially spherical bearing surfaces. The bearingmember1610 can further define a passage orbore1614.
• The bearingmember1610 includes one or moreanti-rotation projections1616aand1616b.Anti-rotation projection1616aand1616bcan project from anexterior surface1618 of the bearingmember1610. Theexterior surface1618 of the bearingmember1610 includesgroove1620. Thegroove1620 can cooperate or hold a locking orfixation ring1624 relative to the bearingmember1610. Thegroove1620 and thelocking ring1624 are a holding member or mechanism to assist in holding the bearingmember1610 within thecage1604. Thelocking ring1624 can also optionally includeanti-rotation projections1626aand1626b.
• Either theanti-rotation projections1616aand1616bor theanti-rotation projections1626aand1626b, can engage anti-rotation depressions orgrooves1630aand1630bincluded in an interior surface1632 of thecage1604. Passage orentry region1634aand1634bcan also be defined in a sidewall of thecage1604. The interior surface1632 includes a locking orfixation groove1640 can also forms part of the holding member or mechanism.
• The bearingmember1610 can be positioned in thecage1604 before or after thelocking ring1624 is positioned within thegroove1620 of the bearingmember1610. According to various embodiments, however, thelocking ring1624 can be positioned within the lockingring groove1620. Thelocking ring1624 can then be compressed prior to or during movement of the bearingmember1610 and lockingring1624 into thecage1604. When thelocking ring1624 engages or is positioned near thegroove1640, thelocking ring1624 can relax or expand to engage at least a portion of or move into a portion of agroove1640.
• Thelocking ring1624 has a ring thickness1644 allowing a first portion of thering1624 to be positioned within thegroove1640 and a second portion of thering1624 to be positioned within thegroove1620 substantially simultaneously. By positioning thelocking ring1624 in both of thegrooves1620 and1640, thelocking ring1624 holds the bearingmember1610 within thecage1604. Thus, thelocking ring1624, alone, can be provided to hold the bearingmember1610 in thecage1604. Other holding mechanisms can, however, be provided.
• The anti-rotation projections, such as theanti-rotation projection1616aand1616b, can assist in minimizing or eliminating rotation of the bearingmember1610 within thecage1604. A set or lockingscrew1646 can, however, also be positioned within apassage1648 defined in thesecond stem structure1600 to engage an anti-rotation cam orsurface1650 of the bearingmember1610. Theset screw1646 can also work as the holding member or mechanism. In this way, the bearingmember1610 can be held, with respect to thecage1604, both transversely, preventing movement out of thecage1604, and rotationally once the bearingmember1610 is positioned within thecage1604.
• As discussed above, the bearingmember1610 can be provide as an ulnar bearing member, and thesecond stem assembly1600 can be provided as an ulnar prosthesis for implantation into a human patient. Accordingly, the bearingmember1610 can include the various features, discussed above. In addition, bearingmember1610 is modular or separate from thecage1604 and can provide for flexibility and selection by the user during a procedure. For example, the kit can include a plurality of the bearingmembers1610 each including different characteristics, such as different bearing surfaces defined around central axes at varying angles. The user can then select the appropriate bearing member for implantation into the patient. Additionally, the modular members or portions allow for trialing to determine or achieve the best or optimum configuration of a prosthesis during an operative procedure.
• It will be understood that first and second stem structures and bearing components are described according to various embodiments. The various stem structures, however, can also be combined in selected and appropriate manners for a selected procedure. Thus, each stem structure can be augmented to include any or all features discussed above. Similarly, each of the bearing components can be augments to include any or all of the features discussed above.
• With reference now toFIGS. 53-59, a linkedstem assembly1700 according to additional features is shown. Thestem assembly1700 can include anulna stem component1702, a bearingmember1704, a ring member1706 (FIG. 54) and afastener1708. Theulna stem component1702 can include an annular cage orenclosed structure1710 that can couple with or hold the bearingmember1704 in a selected position. The bearingmember1704 can have abearing surface1712 that can include two faces or opposing partially- or semi-spherical bearing surfaces. A throughbore orpassage1714 can also be defined through the bearingmember1704. The bearing surfaces1712 and thepassage1714 can have any appropriate configuration, including those discussed above. In one example, thebearing surface1712 can include two opposed bearing sections defined around axes that are at an angle relative to one another.
• The bearingmember1704 can include radially extending tabs1716a-1716cformed on an exterior surface1718. In one example, the tabs1716a-1716ccan extend to medial andlateral edges1720 and1722, respectively, of the bearingmember1704. Eachtab1716a,1716band1716care collectively defined by a pair oftabs1716a,1716band1716cseparated by adepression1719a,1719band1719c, respectively. Agroove1724 can be formed around the outer diameter of the bearingmember1704. In one example, thegroove1724 can be generally centered between the medial andlateral edges1720 and1722 of the bearingmember1704. As will become appreciated, thegroove1724 is configured to at least partially receive thering member1706. The tabs1716a-1716ccan be positioned 120° apart around the bearingmember1704. The tabs1716a-1716ccan extend at aheight1726 above the exterior surface1718 of the bearingmember1704. The bearingmember1704 can be formed of ultra high molecular weight polyethylene (UHMWPE) or polyetheretherketone (PEEK).
• The tabs1716a-1716ccan pass through corresponding tab entries1730a-1730cformed in asidewall1732 of theannular cage1710. Thesidewall1732 can extend between amedial edge1734 and alateral edge1736 of theannular cage1710. Agroove1738 can be formed concentrically around the inner diameter orsidewall1732 of theannular cage1710. In one example, thegroove1738 can be generally centered between themedial edge1734 and thelateral edge1736. As will be discussed herein, the bearingmember1704 can be held within theannular cage1710 with thering member1706 partially nesting into thegroove1724 provided on the bearingmember1704 and thegroove1738 provided on theannular cage1710.
• Theulna stem component1702 can include a radiallycompressible locking mechanism1739. The radiallycompressible locking mechanism1739 includes a disconnect or cut1740 formed completely through theannular cage structure1710 from anouter surface1742 to thesidewall1732. In one example, thecut1740 can be machined in a subsequent step after machining theulna stem component1702. The radiallycompressible locking mechanism1739 can also include a threadedfastener passage1744 that is provided in theulna stem component1702 and traverses thecut1740. A counter-bore1746 can be formed on theulna stem component1702 for nestingly receiving thefastener1708. As will become appreciated from the following discussion, theannular cage1710 is configured to slightly expand thesidewall1732 radially outwardly during assembly of the bearingmember1704 and subsequently retract radially inwardly upon advancement of thefastener1708 through thefastener passage1744 in the assembled position.
• With specific reference toFIGS. 55-59, an exemplary method of assembling the bearingmember1704 into theannular cage1710 of theulna stem component1702 will now be discussed. Initially, the bearingmember1704 can be selected from a group or kit of bearing members, such that an appropriate material, configuration, size and other material or geometrical considerations can be satisfied. For example, as discussed above, the bearingsurfaces1712 can include a multiple and angled bearing surface portion. A plurality of bearingmembers1704 can be provided to include a plurality of angles between respective central axes of the bearing surfaces defining thebearing surface1712. The user can select the bearingmember1704 prior to or during a procedure based upon the patient's anatomy. Various other purposes for providingmodular bearing members1704 can also be provided and are discussed above.
• Once the desiredbearing member1704 has been selected, thering member1706 can be positioned at least partially into thegroove1724 formed on the bearing member1704 (FIG. 55). In some examples, thering member1706 can be slightly expanded radially outwardly to advance past the tabs1716a-1716cuntil reaching a location aligned with thegroove1724. Next, a surgeon can positively align the tabs1716a-1716cof the bearingmember1704 with the tab entries1730a-1730cof theulna stem component1702. Thelateral edge1722 of the bearingmember1704 can then be advanced past themedial edge1734 of theulna stem component1702 until a position where thering member1706 comes into contact with themedial edge1734 of theulna stem component1702. At this point, a surgeon can compress manually thering member1706 further into thegroove1724 on the bearingmember1704 and/or, continue to advance the bearingmember1704 into theannular cage1710 causing thering member1706 to compress further into thegroove1724 and reach an outer diameter that is generally less than the inner diameter of the sidewall1732 (FIG. 56). The bearingmember1704 is then further advanced into theannular cage1710 until reaching a position where thering member1706 aligns with thegroove1738 formed around thesidewall1732 of theannular cage1710. Once thering member1706 aligns with thegroove1738 on thesidewall1732, thering member1706 will expand radially outwardly to its original static position where at least a portion of thering member1706 extends into thegroove1738 of theannular cage1710 and at least partially extends into thegroove1724 of the bearing member1704 (FIG. 57).
• Next, with specific reference toFIGS. 58 and 59, the radiallycompressible locking mechanism1739 will be further described. Thefastener1708 is threadably advanced into thefastener passage1744 of theulna stem component1702. Threadable advancement of thefastener1708 into thefastener passage1744 causes the inner diameter of thesidewall1732 to be reduced as agap1748 defined by opposing sidewalls of thecut1740 closes. Once thefastener1708 has been advanced sufficiently to close the gap provided by thecut1740, thering member1706 becomes further nested within each of thegrooves1724 and1738 of the bearingmember1704 and theannular cage1710, respectively. In the assembled position, thering member1706 inhibits medial/lateral motion of the bearingmember1704 relative to thesidewall1732 of theannular cage1710. Additionally, the tabs1716a-1716cof the bearingmember1704 cooperate with the tab entries1730a-1730cto inhibit rotational motion of the bearingmember1704 within theannular cage1710. Thestem assembly1700 can be used in conjunction with any of the bearing and/or stem components described herein. While the radiallycompressible locking mechanism1739 has been described as compressing theannular cage1710 by advancement of thefastener1708 into thefastener passage1744, other configurations and mechanisms may be employed to compress theannular cage1710 around the bearingmember1704.
• With reference now toFIG. 60, anulna stem component1702′ constructed in accordance to additional features of the present teachings will now be described. Unless otherwise described, theulna stem component1702′ is constructed similarly to theulna stem component1702 discussed above with respect toFIGS. 54-59. Theulna stem component1702 can include an annular cage orenclosed structure1710′ that can couple with or hold the bearing member1704 (not specifically shown in this figure) in a selected position. Theannular cage1710′ can have an innercylindrical sidewall1732′ that extends between amedial edge1734′ and alateral edge1736′. Theulna stem component1702′ can have a disconnect or cut1740′ that is formed completely through theannular cage structure1710′ from anouter surface1742′ to thesidewall1732′. Thecut1740′ of theulna stem component1702′ has a V-shaped profile. The V-shaped profile decreases shear loads experienced on theulna stem component1702′. In this way, any shear loads experienced between a bearingmember1704 assembled in theannular cage1710′ and theulna stem component1702′ can be taken up by not only thefastener1708 but by the structure of theulna stem component1702′ as a result of the opposing surfaces created by the V-shaped profile in thecut1740′. It will be appreciated that thecut1740′ having the V-shaped profile can be included on any of the ulna stem components disclosed herein.
• With reference now toFIGS. 61-67, a linkedstem assembly1800 according to additional features is shown. Thestem assembly1800 can include anulna stem component1802, a bearingmember1804, and afastener1808. Theulna stem component1802 can include an annular cage orenclosed structure1810 that can couple with or hold the bearing member1804 (or the bearingmember1804′) in a selected position. The bearingmember1804 can have abearing surface1812 that can include two faces or opposing partially- or semi-spherical bearing surfaces. The throughbore orpassage1814 can also be defined through the bearingmember1804. The bearing surfaces1812 and thepassage1814 can have any appropriate configuration, including those discussed above. In one example, thebearing surface1812 can include two bearing sections defined around axes that are at an angle relative to one another. The bearingmember1804′ can have similar features as the bearingmember1804. In this way, similar features are simply identified with a “prime” suffix on the reference numeral.
• The bearingmember1804 can include tabs1816a-1816cformed on anexterior surface1818. In one example, the tabs1816a-1816ccan extend to medial andlateral edges1820 and1822, respectively, of the bearingmember1804. Aradial depression1824 can be formed around the outer diameter of the bearingmember1804. In one example, theradial depression1824 can be in the form of a negative V-shape. The tabs1816a-1816ccan radially extend at aheight1826 above theexterior surface1818 of the bearingmember1804. The bearingmember1804 can be formed of ultra high molecular weight polyethylene (UHMWPE) or polyetheretherketone (PEEK).
• The tabs1816a-1816ccan pass through tab entries1830a-1830cformed in asidewall1832 of thecage1810 and rest therein. Thesidewall1832 can extend between amedial edge1834 and alateral edge1836 of thecage1810. Aradial protrusion1838 can be formed around the inner diameter orsidewall1832 of thecage1810. In one example, theradial protrusion1838 can be in the form of a positive V-shape. In one example, theradial protrusion1838 can be generally centered between themedial edge1834 and thelateral edge1836. As will be described herein, theradial depression1824 formed on the bearingmember1804 can nestingly receive theradial protrusion1838 formed on thesidewall1832 of thecage1810 to positively locate the bearingmember1804 inside thecage1810.
• Theulna stem component1802 can include a radiallycompressible locking mechanism1839. The radiallycompressible locking mechanism1839 includes a disconnect or cut1840 formed completely through theannular cage structure1810 from anouter surface1842 to thesidewall1832. Again, the cut1749 may be formed through thecage structure1810 by a supplemental machining step. The radiallycompressible locking mechanism1839 can include a threadedfastener passage1844 that is provided in theulna stem component1802 and traverses the cut1749. A counter-bore1846 can be formed on theulna stem component1802 for nestingly receiving thefastener1808. As will become appreciated from the following discussion, thecage1810 is configured to slightly expand thesidewall1832 radially outwardly during assembly of the bearingmember1804 and subsequently retract radially inwardly upon advancement of thefastener1808 through thefastener passage1844 in the assembled position.
• With specific reference now toFIGS. 63-65, an exemplary method of assembling the bearingmember1804 into thecage1810 of theulna stem component1802 will be discussed. Initially, the bearingmember1804 can be selected from a group or kit of bearing members (such as including the bearingmember1804′), such that an appropriate material, configuration, size and other material or geometrical considerations can be satisfied. For example, as discussed above, the bearingsurfaces1812 can include a multiple and angled bearing surface portion. A plurality of bearingmembers1804 can be provided to include a plurality of angles between respective central axes of the bearing surfaces defining thebearing surface1812. The user can select the bearingmember1804 prior to or during a procedure based upon the patient's anatomy. Various other purposes for providingmodular bearing members1804 can also be provided and are discussed above.
• Once the desiredbearing member1804 has been selected, a surgeon can align the tabs1816a-1816cof the bearingmember1804 with the tab entries1830a-1830cof theulna stem component1802. Thelateral edge1822 of the bearingmember1804 can then be advanced passed themedial edge1834 of theulna stem component1802 until a position where theradial protrusion1838 of thecage1810 is aligned with theradial depression1824 of the bearingmember1804. Because theradial protrusion1838 is in the form of a positive V-shape and theradial depression1824 is in the form of a complementary negative V-shape, a user is given positive tactile feedback when theradial protrusion1838 is satisfactorily received into theradial depression1824 of the bearingmember1804. It will be appreciated by those skilled in the art that while theradial depression1824 has been described as being provided on the bearingmember1804 and theradial protrusion1838 has been described as being provided on thecage1810, the respective depression and protrusion may be located on opposite components. Furthermore, while therespective depression1824 andprotrusion1838 have been illustrated and described as having a V-shape geometry, other geometries may be provided that can establish a complementary interlocking profile.
• Next, with specific reference toFIGS. 66 and 67, the radiallycompressible locking mechanism1839 will be further described. Thefastener1808 can be threadably advanced into thefastener passage1844 of theulna stem component1802. Threadable advancement of thefastener1808 into thefastener passage1844 causes the inner diameter of thesidewall1832 to be reduced as agap1848 defined by thecut1840 closes. Once thefastener1808 has been advanced sufficiently to close the gap provided by thecut1840, the bearingmember1804 is further secured in a confined position within thecage1810. In the assembled position, the interface between theradial depression1824 and theradial protrusion1838 inhibits medial/lateral motion of the bearingmember1804 relative to thesidewall1832 of thecage1810. Additionally, the tabs1816a-1816cof the bearingmember1804 cooperate with the tab entries1830a-1830cto inhibit rotational motion of the bearingmember1804 within thecage1810. Thestem assembly1800 can be used in conjunction with any of the bearing and/or stem components described herein. While the radiallycompressible locking mechanism1839 has been described as compressing thecage1810 by advancement of thefastener1808 into thefastener passage1844, other configurations and mechanisms may be employed to compress thecage1810 around the bearingmember1804.
• With reference now toFIGS. 68-72, a modular unlinkedulnar stem assembly1900 according to one example of the present teachings will be described. In general, the modular unlinkedulnar stem assembly1900 can include astem1902, an articulatingcomponent1904, aplate1906 and afastener1908. As will become appreciated from the following discussion, the articulatingcomponent1904 can be modular such that a series of articulating components can be provided that are selectively attachable to thestem1902 according to a specific patient's needs. The modular unlinkedulnar stem assembly1900 can be favorable in some circumstances as it has the potential to remove less native bone than other elbow prostheses such as a semi-constrained total elbow, for example. Furthermore, the modular unlinkedulnar stem assembly1900 can be favorable in circumstances where one side of the elbow joint includes satisfactory bone and/or cartilage and it is only desirable to replace the other side of the elbow joint.
• With specific reference now toFIG. 69, exemplary features of thestem1902 will be described. Thestem1902 can generally include anulnar ring1910 that is in the form of a partial or semi-circular cylinder. Thestem1902 can further comprise afirst retaining mechanism1912 having laterally extendingrails1914 that extend around theulnar ring1910 from afirst end1916 to asecond end1918. Thesecond end1918 of therails1914 can include astop1920 that has a pair of outwardly extending stop surfaces1922. Theulnar ring1910 can also include aconcave slide surface1924 and a threadedbore1926 formed thereon.
• With continued reference toFIG. 69, the articulatingcomponent1904 will be described in greater detail. In general, the articulatingcomponent1904 can include abody1930 that generally takes the shape of a partial or semi-circular cylinder complementary to the shape of theulnar ring1910. The articulatingcomponent1904 includes asecond retaining mechanism1932 having a pair oflateral walls1934 that cooperate to define a semi-circulararcuate channel1936. Thelateral walls1934 extend from afirst end1938 to asecond end1940. A pair ofcatches1942 are formed at the respective second ends1940 of thearms1934. Thecatches1942 have catch surfaces1944. The articulatingcomponent1904 includes aconvex slide surface1948 that extends between the respectivelateral arms1934. The articulatingcomponent1904 can be formed of ultra high molecular weight polyethylene (UHMWPE) or polyetheretherketone (PEEK).
• Turning now toFIGS. 70-72, an exemplary method of attaching the articulatingcomponent1904 to thestem1902 will be described. At the outset, once a surgeon has selected the appropriate articulatingcomponent1904 that satisfies a desired articulating surface geometry for a particular patient, thesecond end1940 is located generally adjacent to thefirst end1916 of therails1914 of the stem1902 (FIG. 70). Next, the surgeon rotates the articulatingcomponent1904 in a counter-clockwise direction about an axis1950 (as viewed inFIGS. 70-71) such that therails1914 of thefirst retaining mechanism1912 locate into thechannel1936 of asecond retaining mechanism1932. Continued rotation of the articulatingcomponent1904 around therails1914 can additionally include slidable engagement of theconvex slide surface1948 of the articulatingcomponent1904 along theconcave slide surface1924 of theulnar ring1910. The articulatingcomponent1904 is further rotated until thecatch1942 on the articulatingcomponent1904 engages thestop1920 provided on thesecond end1918 of therails1914. In this way, the catch surfaces1944 of the articulatingcomponent1904 can rest on the stop surfaces1922 of the rails1914 (FIG. 72). Next, a surgeon can advance thefastener1908 through a passage1954 (as best shown inFIG. 69) of theplate1906 and threadably advance thefastener1908 into the threadedbore1926 of thestem1902 to capture and retain the articulatingcomponent1904.
• With reference now toFIGS. 73-77, another exemplary modular unlinkedulnar stem assembly2000 constructed in accordance to additional features of the present teachings will be described. The modular unlinkedulnar stem assembly2000 can generally comprise astem2002, an articulatingcomponent2004, anintermediate rail component2006, and afastener2008. The drawings depict the articulatingcomponent2004 and theintermediate rail component2006 as separate for illustrative purposes. The articulatingcomponent2004 and theintermediate rail component2006 are molded together as a single piece. Thestem1902 can include anulnar ring2010 that is generally in the shape of a partial or semi-circular cylinder. Thestem2002 can include afirst retaining mechanism2012 that includes agroove2014 formed in theulnar ring2010. Alip2016 is provided at a terminal end of thegroove2014 on thefirst retaining mechanism2012. Theulnar ring2010 can further comprise a threadedbore2026.
• As with the configurations described above, the articulatingcomponent2004 can be modular. In this way, a series of articulating components can be provided that each have various geometries that can be selected according to a particular patient's needs. Furthermore, while the articulatingcomponent2004 and therail component2006 are shown as distinct components, they may be provided as an integrally formed piece. In one example, therail component2006 can be formed of biocompatible metal material such as titanium and the articulatingcomponent2004 can be formed of UHMWPE or PEEK. As described above, in one example, therail component2006 can be molded to the articulatingcomponent2004. Other techniques may be utilized to connect therail component2006 to the articulatingcomponent2004.
• Therail component2006 can generally comprise asecond retaining mechanism2032 in the form of arail2036. Thesecond retaining mechanism2032 can further comprise afinger2038 that is formed at a terminal end of therail2036. On an end opposite of thefinger2038, therail component2006 can include aplate2040 having aneyelet2042 formed there through. Therail component2006 includes anannular channel2044 that can facilitate molding with the articulatingcomponent2004.
• With specific reference now toFIG. 75, another modular unlinkedulnar stem assembly2000′ is shown. Like features are illustrated with similar reference numerals as shown and described above with respect toFIG. 74 and having a “prime” suffix. Thestem assembly2000′ can include arail component2006′ shown having asecond retaining mechanism2032′ that includes arail2036′ and afinger2038′. Aneyelet2042′ is provided on therail component2006′. The articulatingcomponent2004′ and therail component2006′ are shown as separate pieces however they are molded together as a single unit.
• Turning now toFIGS. 76 and 77, an exemplary method of assembling the articulatingcomponent2004 to theulnar ring2010 of thestem2002 will be described. In the examples shown inFIGS. 76 and 77, the articulatingcomponent2004 and therail component2006 are shown as an integral piece. At the outset, arail2036 of therail component2006 is aligned for receipt into thegroove2014 provided on theulnar ring2010. Next, the articulatingcomponent2004 andrail component2006 are advanced into contact with thefirst retaining mechanism2012 of thestem2002. Explained further, therail2036 is advanced into thegroove2014 while thefinger2038 locates around thelip2016 on theulnar ring2010. At this point, thefastener2008 is advanced through theeyelet2042 and threadably advanced into the threadedbore2026. As can be appreciated, the first andsecond retaining mechanisms2012 and2032 cooperate to maintain the articulatingcomponent2004 in a secure position.
• With reference now toFIGS. 78 and 79, another modular unlinkedulnar stem assembly2100 according to additional features of the present teachings will be described. The modular unlinkedulnar stem assembly2100 can generally include astem2102, an articulatingcomponent2104, and afastener2108. The articulatingcomponent2104 further comprises arail2136. Thestem2102 can include anulnar ring2110 that is generally in the form of a partial cylinder and has acatch2120 formed at an end thereof. Agroove2114 is formed in theulnar ring2110. In one example, thecatch2120 can cooperate with thefastener2108 to provide afirst retaining mechanism2112. The articulatingcomponent2104 can include asecond retaining mechanism2132 that includes afoot portion2140 formed at an opposite end of aneck portion2142. According to one example of assembling the articulatingcomponent2104 to theulnar ring2110 of thestem2102, the articulatingcomponent2104 can be rotated in a counter-clockwise direction as viewed inFIG. 78 until thefoot portion2140 engages thecatch2120. Next, thefastener2108 is threadably advanced into the threadedbore2126 to further capture the articulatingcomponent2104 relative to theulnar ring2110 of thestem2102.
• With reference now toFIGS. 80 and 81, another unlinkedulnar stem assembly2200 according to additional features of the present teachings will be described. The unlinkedulnar stem assembly2200 can be configured to be inserted into aprepared opening2202 of anulna2204. The unlinkedulnar stem assembly2200 generally comprises abody portion2210 and a C-shapedsupport frame2212. Thebody portion2210 can be in the form of astem structure2213 that includes astem portion2214. Thebody portion2210 can have aretaining mechanism2220 formed thereon. Theretaining mechanism2220 can generally include a first portion orlongitudinal member2222 and a second portion orlongitudinal member2224. An articulatingcomponent2226 can be connected to the C-shapedsupport frame2212. In one example, the firstlongitudinal member2222 can generally be in the form of an elongated planar member extending in a superior/inferior direction. The firstlongitudinal member2222 can have a first medial/lateral dimension2228. The secondlongitudinal member2224 can generally be in the form of an elongated planar member that is transverse to the firstlongitudinal member2222 and extends generally in the medial/lateral direction. The secondlongitudinal member2224 can have a second medial/lateral dimension2229. The second dimension2229 is greater than the first dimension2228.
• The first and secondlongitudinal members2222 and2224, respectively, can cooperate to provide a T-shaped cross-section of theretaining mechanism2220. In one example, thebody portion2210 can be formed of biocompatible metal material, such as titanium. The articulatingcomponent2226 can be formed of UHMWPE or PEEK. According to one configuration, the articulatingcomponent2226 can be molded to the C-shapedsupport frame2212. Other methods may be used to interconnect the articulatingcomponent2226 with the C-shapedsupport frame2212. It is also contemplated that the articulatingcomponent2226 can be modular relative to the C-shapedsupport frame2212. In this way, in some examples, a surgeon may select an articulatingcomponent2226 having properties suitable for a given patient's needs and intraoperatively connect the articulatingcomponent2226 with the C-shapedsupport frame2212.
• With continued reference toFIGS. 80 and 81, theulna2204 will be described in greater detail. Theulna2204 can be shaped to include a C-shapedreceiving portion2230 that has a geometry suitable to receive the C-shapedsupport frame2212 of the unlinkedulnar stem assembly2200. Theopening2202 can be formed, such as with a punch, reamer or other drilling device that is operable to form a cavity having a shape that is complementary with theretaining mechanism2220. In this way, theopening2202 generally has a firstlongitudinal cavity portion2232 and a secondlongitudinal cavity portion2234 that collectively provides an elongated T-shaped cavity for receiving thestem structure2212 andretaining mechanism2220 of the unlinkedulnar stem assembly2200 as shown inFIG. 81. In one example, bone cement may be used in theopening2202. Additionally, or alternatively, the outer surface of theretaining mechanism2220 can be porous for facilitating boney ingrowth.
• As best illustrated inFIG. 81, the secondlongitudinal member2224 can be confined within the firstlongitudinal cavity portion2232 to inhibit movement of theunlinked stem assembly2200 in an anterior direction when implanted into theulna2204. Theunlinked stem assembly2200 is also inhibited from movement in other directions, such as the medial and lateral directions upon receipt into theopening2202. It is appreciated that the T-shaped cross-section of theretaining mechanism2220 and thecorresponding opening2202 may be formed differently. Other cross-sections are contemplated, such as a dove-tail cross-section, a curved cross-section or other cross-sections suitable to provide a secure relationship between theretaining mechanism2220 and theopening2202.
• With reference now toFIGS. 82 and 83, another unlinkedulnar stem assembly2250 according to additional features of the present teachings will be described. The unlinkedulnar stem assembly2250 can be configured to be inserted into aprepared opening2252 of anulna2204. The unlinkedulnar stem assembly2250 generally comprises abody portion2260 and a C-shapedsupport frame2262. Thebody portion2260 can be in the form of astem structure2263 that includes astem portion2264. Thebody portion2260 can have aretaining mechanism2270 formed thereon. Theretaining mechanism2270 can generally include a first portion orlongitudinal member2272 and a second portion orlongitudinal member2274. The secondlongitudinal member2274 can generally be in the form of acylinder2275. An articulatingcomponent2276 can be connected to the C-shapedsupport frame2262. In one example, the firstlongitudinal member2272 can generally be in the form of an elongated planar member extending in a superior/inferior direction. The firstlongitudinal member2272 can have a first medial/lateral dimension2277. Thecylinder2275 of the secondlongitudinal member2274 can have portions that extend in a direction that is transverse to the firstlongitudinal member2272. The secondlongitudinal member2274 can have a second medial/lateral dimension2278. The second dimension2278 is greater than the first dimension2277. Theretaining mechanism2270 can therefore provide a substantially non-linear cross-section.
• In one example, thebody portion2260 can be formed of biocompatible metal material, such as titanium. The articulatingcomponent2276 can be formed of UHMWPE or PEEK. According to one configuration, the articulatingcomponent2276 can be molded to the C-shapedsupport frame2262. Other methods may be used to interconnect the articulatingcomponent2276 with the C-shapedsupport frame2262. It is also contemplated that the articulatingcomponent2276 can be modular relative to the C-shapedsupport frame2272. In this way, in some examples, a surgeon may select an articulatingcomponent2276 having properties suitable for a given patient's needs and intraoperatively connect the articulatingcomponent2276 with the C-shapedsupport frame2262.
• With continued reference toFIGS. 82 and 83, theulna2254 will be described in greater detail. Theulna2254 can be shaped to include a C-shapedreceiving portion2280 that has a geometry suitable to receive the C-shapedsupport frame2262 of the unlinkedulnar stem assembly2250. Theopening2252 can be formed, such as with a punch, reamer, or other drilling device that is operable to form a cavity having a shape that is complementary with theretaining mechanism2270. In this way, theopening2252 generally has a firstlongitudinal cavity portion2282 having a cylindrical cross-section, and a secondlongitudinal cavity portion2284 having a generally planar cross-section that collectively provide a shape that is suitable for receiving thestem structure2263 andretaining mechanism2270 of the unlinkedulnar stem assembly2250 as shown inFIG. 82. Once theretaining mechanism2270 is suitably inserted into theopening2252, abone screw2240 is inserted into athroughbore2242 provided in thecylinder2275. Thebone screw2240 is then threadably advanced into theulna2254 until ahead2244 of thebone screw2240 rests on a counterbore ledge2246 formed in thecylinder2275.
• In one example, bone cement may be used in theopening2252. Additionally, or alternatively, the outer surface of theretaining mechanism2270 can be porous for facilitating bony ingrowth. As best illustrated inFIG. 83, the secondlongitudinal member2274 can be confined within the firstlongitudinal cavity portion2282 to inhibit movement of the unlinkedulnar stem assembly2250 in an anterior direction when implanted into theulna2254. The unlinkedulnar stem assembly2250 is also inhibited from movement in other directions, such as the medial and lateral directions upon receipt into theopening2252. It is appreciated that the cylindrical shaped cross-section of the secondlongitudinal member2274 of theretaining mechanism2270 and thecorresponding opening2254 may be formed differently.
• With reference now toFIGS. 84 and 85, a bearingremoval tool kit2300 constructed in accordance to additional features of the present teachings will be described. In general, the bearingremoval tool kit2300 can include a series of tools that, in various combinations, can be used to assist a surgeon in compressing a lock ring2302 (FIG. 85) such that a bearingmember1704 can be subsequently urged (in the medial/lateral direction) out of anannular cage1710 of anulna stem component1702. As will be described, while the bearingremoval tool kit2300 is shown cooperating with thelock ring2302 andulna stem component1702, the various tools of the bearingremoval tool kit2300 can be used to compress lock rings having different configurations, such as shown herein at reference numeral1706 (FIG. 54) or at reference numeral1624 (FIG. 51). Likewise, while the bearingremoval tool kit2300 is shown for use during removal of the bearingmember1704, the bearingremoval tool kit2300 can be used to urge other bearing members having various shapes, such as disclosed herein including the bearing member1610 (FIG. 51).
• The bearingremoval tool kit2300 can generally comprise afirst tool2310, asecond tool2312, athird tool2314, a series ofextractor pins2316 and anextractor plate2318. Thefirst tool2310 can generally take the shape of forceps and, as will be described, can be used to hold and position the extractor pins2316 relative to theulna stem component1702 and the bearingmember1704. Thefirst tool2310 can include afirst arm2320 having afirst handle2322 at one end and ahalf ring2324 on an opposite end. Asecond arm2326 can have asecond handle2328 at one end and ahalf ring2330 at an opposite end. A pair of lockingmembers2332 and2334 can be formed on thefirst handle2322 and thesecond handle2328, respectively. The first andsecond arms2320 and2326 can be pivotally coupled at apivot2336. The opposed half rings2324,2330 have opposed arcuate surfaces that engage acylindrical neck2392 of thepins2316 as will be described.
• Thesecond tool2312 can be used to further urge the extractor pins2316 between theannular cage1710 of theulna stem component1702 and the bearingmember1704 as shown inFIGS. 87 and 88. Thesecond tool2312 can also be generally in the form of forceps. Thesecond tool2312 can have afirst arm2340 having afirst handle2342 at one end and anelongated locating finger2344 at an opposite end. The locatingfinger2344 can include anub2345 provided thereon. Thesecond tool2312 can further include asecond arm2346 having asecond handle2348 at one end and arectangular locating pad2350 at an opposite end. Thelocating pad2350 can define arecess2352. The first andsecond arms2340 and2346 can be pivotally coupled at apivot2356.
• Thethird tool2314 can be used to urge the bearingmember1704 out of theannular cage1710 once thelock ring2302 has been compressed as shown inFIGS. 91 and 92. Thethird tool2314 can also take the general shape of forceps. Thethird tool2314 can include afirst arm2360 having afirst handle2362 at one end and arectangular locating pad2364 at an opposite end. Thethird tool2314 can also have asecond arm2366 having asecond handle2368 at one end and aspherical plunger2370 at an opposite end. The first andsecond arms2360 and2366 can be pivotally coupled at apivot2372.
• Theextractor pin2316 can be used to slidably advance between theannular cage1710 of theulna stem component1702 and the bearingmember1704. During such slidable advancement, theextractor pin2316 can ramp over an outer radial surface of thelock ring2302 to compress thelock ring2302 as will be further described. Theextractor pin2316 generally includes ashaft2378 that has afirst end2380 and asecond end2382. Thefirst end2380 can have aninterference portion2384 in the general shape of a conical tip. Thesecond end2382 can include ahead2386 that includes afirst collar2388, asecond collar2390 and acylindrical neck2392 therebetween.
• Theextractor plate2318 can be used similarly to the extractor pins2316 when it is desired to concurrently or simultaneously advance a series of extractor pins between theannular cage1710 of theulna stem component1702 and the bearingmember1704 instead of sequentially locating individual extractor pins2316. In general, theextractor plate2318 includes aplate body2394 having a plurality ofextractor pins2396 extending from afirst surface2398 of theplate body2394. Each of the extractor pins2396 includes first ends2400 havinginterference portions2402.
• With reference now toFIGS. 85 and 86, initial positioning of the extractor pins2316 with thefirst tool2310 will be described according to one example. Again, it will be appreciated that while thefirst tool2310 is being described as initially locating the extractor pins2316, the extractor pins2316 may be initially located with other tools or simply by a surgeon's fingers. At the outset, the half rings2324 and2330 of thefirst tool2310 can be located around theneck2392 at thesecond end2382 of theextractor pin2316. Next, thefirst end2380 of theextractor pin2316 can be advanced into thedepression1719bbetween thetabs1716bof the bearingmember1704. According to one example, theextractor pin2316 can be advanced in the medial/lateral direction a distance until initially engaging thelock ring2302. While thesecond tool2312 is described herein as further advancing the extractor pin to compress thelock ring2302, it is contemplated that in some examples, thefirst tool2310 can optionally be used to further advance the extractor pins2316 to compress the lock ring.
• With reference now toFIGS. 87 and 88, thesecond tool2312 of the bearingremoval tool kit2300 will be described as further advancing the extractor pins2316 between theannular cage1710 of theulna stem component1702 and the bearingmember1704 to compress thelock ring2302. Initially, therecess2352 of thelocating pad2350 can be placed around thefirst collar2388 of thesecond end2382 of theextractor pin2316. Thenub2345 of the locatingfinger2344 can also be located at thedepression1719b. The first end second handles2342 and2348 can then be urged together, such that the first andsecond arms2340 and2346 rotate or pivot around thepivot2356 to create a clamping force between the locatingfinger2344 and thelocating pad2350. The clamping force causes theinterference portion2384 of theextractor pin2316 to ramp across a radialouter surface2410 of thelock ring2302 and thereby compress thelock ring2302 into thegroove1724 of the bearingmember1704. Once all of the extractor pins2316 have been advanced, thelock ring2302 will be compressed into thegroove1724 and therefore moved to a position out of thegroove1738 of theulna stem component1702. According to other methods, oneextractor pin2316 can be slidably advanced in the medial (or lateral) direction through thedepression1719bto the position shown inFIG. 88. Next, another longitudinal member (i.e., a pin, nail, shaft, etc.) can be slidably advanced in the opposite direction through thesame depression1719bto push out and take the place of theextractor pin2316. In such a method, only oneextractor pin2316 is needed as it can be used in sequence through all of thedepressions1719a,1719band1719c. It is also appreciated that while threedepressions1719a,1719band1719chave been described as receiving threeextractor pins2316, using more or less extractor pins and depressions are contemplated.
• With reference now toFIGS. 89 and 90, an alternate method of compressing thelock ring2302 using theextractor plate2318 will be described. Again, theextractor plate2318 can be used when it is desired to concurrently or simultaneously pass a series of pins between theannular cage1710 of theulna stem component1702 and the bearingmember1704. When using theextractor plate2318, a surgeon can initially position the respectivefirst ends2400 of the extractor pins2396 into the correspondingdepressions1719a,1719band1719cof the bearingmember1704. Next, theplate body2394 of theextractor plate2318 can be advanced further between theannular cage1710 of theulna stem component1702 and the bearingmember1704. In doing so, therespective interference portions2402 slidably advance along theouter surface2410 of thelock ring2302 causing it to compress into thegroove1724 of the bearingmember1704. By compressing thelock ring2302 into thegroove1724 of the bearingmember1704, thelock ring2302 is moved to a position away from thegroove1738 in theulna stem component1702. Theextractor plate2318 can be advanced in the medial/lateral direction by any suitable clamping instrument, such as those disclosed herein or by urging with a surgeon's fingers.
• With reference now toFIGS. 91 and 92, use of thethird tool2314 to urge the bearingmember1704 out of theannular cage1710 after thelock ring2302 has been compressed will be described. In one example, thelocating pad2364 of thefirst arm2360 can be located on one side of theulna stem component1702 and theplunger2370 can be located on the opposite side of theulna stem component1702 and centrally aligned and nested into the bearingmember1704. In one example, a nub similar to the nub2345 (FIG. 87) can be included on thelocating pad2364 for locating into thedepression1719b(FIG. 86). Theplunger2370 can be formed entirely or partially of resilient material. Theplunger2370 can include a metallic substrate having a nylon coating or be formed entirely of a metallic substrate. In other examples, a polymeric material can be provided on theplunger2370. Next, the first andsecond handles2362 and2368 (seeFIG. 84) can be urged together, such that the first andsecond arms2360 and2366 pivot around thepivot2372 and create a clamping force between thelocating pad2364 and theplunger2370. As a result, theplunger2370 forcibly advances the bearingmember1704 in the medial/lateral direction out of theannular cage1710 as shown inFIG. 92. Once the bearingmember1704 is urged out of theannular cage1710, the extractor pins2316 will simply fall away from theannular cage1710 and can be later collected.
• While the description in the specification and illustrated in the drawings are directed to various embodiments, it will be understood that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the teachings and the appended claims. In addition, many modifications may be made to adapt a particular situation or material to the teachings without departing from the scope thereof. Therefore, it is intended that the teachings and claims are not be limited to any particular embodiment illustrated in the drawings and described in the specification, but that the teachings and claims can include any embodiments falling within the foregoing description and the appended claims.

Claims (30)

1. An elbow prosthesis comprising:

a first stem structure operable to be positioned in a first bone of a joint, the first stem structure including:

a first stem portion operable to be positioned the first bone; and

a cage structure formed generally between an inner sidewall and an outer surface;

a first bearing component having an exterior cage opposing surface, wherein the first bearing component is selectively inserted into the cage structure from an insertion position to an assembled position; and

a radially compressible locking mechanism that moves the cage structure radially inwardly from a first location toward the first bearing component into a second location.

2. The elbow prosthesis ofclaim 1 wherein the radially compressible locking mechanism comprises opposing surfaces on the cage structure that define a disconnect formed entirely through the cage structure from the inner sidewall to the outer surface.

3. The elbow prosthesis ofclaim 2 wherein the radially compressible locking mechanism further comprises a fastener that threadably advances into an engaged position with the cage structure and reduces a gap defined between the opposing surfaces of the disconnect while radially contracting the cage structure around the first bearing.

4. The elbow prosthesis ofclaim 2 wherein at least one of the opposing surfaces of the disconnect is non-linear from the inner sidewall to the outer surface.

5. The elbow prosthesis ofclaim 1 wherein the inner sidewall of the cage structure has a first groove and the exterior cage opposing surface has a second groove that opposes the first groove in the assembled position.

6. The elbow prosthesis ofclaim 4, further comprising a lock ring that partially nests within each of the first and second grooves in the assembled position.

7. The elbow prosthesis ofclaim 4 wherein one of the cage structure or the first bearing component includes at least one tab entry that slidably accepts at least one tab formed on the other of the cage structure or the first bearing component in the assembled position.

8. The elbow prosthesis ofclaim 7 wherein the at least one tab and tab entry, respectively, cooperate to inhibit rotation of the first bearing around the inner sidewall of the cage structure.

9. The elbow prosthesis ofclaim 1 wherein the inner sidewall has a first V-shaped cross-section.

10. The elbow prosthesis ofclaim 9 wherein the exterior cage opposing surface of the first bearing component has a second V-shaped cross-section that cooperatively engages the first V-shaped cross-section to inhibit medial-lateral movement of the first bearing in the assembled position.

11. The elbow prosthesis ofclaim 1, further comprising a second bearing component associated with a second stem structure, the second bearing component operable to cooperatively rotate with the first bearing component, the first stem structure adapted to be implanted into one of a humerus or ulna, the second stem structure adapted to be implanted into the other of the humerus and ulna.

12. An elbow prosthesis comprising:

a stem structure operable to be positioned in a bone of a joint, the stem structure including:

a stem portion operable to be positioned in the bone; and

a C-shaped body portion having a first retaining mechanism formed thereon;

an articulating component having a second retaining mechanism formed thereon; and

wherein the articulating component is rotatably advanced about an axis from an insertion position to an assembled position such that the first and second retaining mechanisms cooperatively interlock to inhibit medial/lateral movement of the articulating component relative to the C-shaped body portion of the stem structure.

13. The prosthesis ofclaim 12 wherein the first retaining mechanism comprises outwardly extending rails formed on the C-shaped body portion.

14. The prosthesis ofclaim 13 wherein the first retaining mechanism further comprises a stop having stop surfaces provided on one end of the rails.

15. The prosthesis ofclaim 14 wherein the second retaining mechanism comprises a channel having a geometry that cooperatively receives the rails of the C-shaped body portion.

16. The prosthesis ofclaim 15 wherein the articulating component comprises a catch having catch surfaces that engage the stop surfaces in the assembled position.

17. The prosthesis ofclaim 15, further comprising a plate and a fastener, the fastener extending through a passage in the plate and threadably coupling to the stem portion, the plate inhibiting rotation of the articulating component from the assembled position to the insertion position.

18. The elbow prosthesis ofclaim 15, further comprising a plurality of articulating components having various geometries, each articulating component of the plurality being selectively coupled to the stem structure.

19. An elbow prosthesis comprising:

a stem structure operable to be positioned in a bone of a joint, the stem structure including:

a stem portion operable to be positioned in the bone; and

a C-shaped body portion having a first retaining mechanism formed thereon;

an articulating component having a second retaining mechanism formed thereon; and

wherein one of the first and second retaining mechanisms comprises a rail and the other of the first and second retaining mechanisms comprises a groove, wherein the articulating component is advanced from an insertion position to an assembled position such that the first and second retaining mechanisms cooperatively interlock to inhibit medial/lateral movement of the articulating component relative to the C-shaped body portion of the stem structure.

20. The elbow prosthesis ofclaim 19 wherein the articulating component comprises a bearing portion and the rail, the rail having a first end including a plate and a second end including a hook.

21. The elbow prosthesis ofclaim 20 wherein the plate includes an eyelet adapted to receive a fastener therethrough, the fastener threadably coupling the articulating component to the stem structure, the hook cooperatively engaging an end of the stem portion at the groove.

22. The elbow prosthesis ofclaim 19, further comprising a plurality of articulating components having various geometries, each articulating component of the plurality being selectively coupled to the stem structure.

23. An elbow prosthesis comprising:

a stem structure operable to be positioned in a bone of a joint, the stem structure including:

a stem portion operable to be positioned in the bone; and

a body portion having a retaining mechanism formed thereon;

an articulating component connected to the body portion; and

wherein the retaining mechanism includes a first portion having a first dimension in a medial/lateral direction and a second portion having a second dimension in the medial/lateral direction, the second dimension being greater than the first dimension, the retaining mechanism operable to be advanced into an opening formed in the bone.

24. The elbow prosthesis ofclaim 23 wherein the first and second portions of the retaining mechanism cooperate to have a substantially T-shaped cross-section.

25. The elbow prosthesis ofclaim 23 wherein the first portion includes a planar elongated member and the second portion includes a substantially cylindrical cross-section.

26. The elbow prosthesis ofclaim 25 wherein the second portion includes a through-bore for receiving a bone screw that threads into the bone.

27. An elbow prosthesis comprising:

a first stem structure operable to be positioned in a first bone of a joint, the first stem structure including:

a first stem portion operable to be positioned in the first bone; and

a cage structure formed generally between an inner sidewall and an outer surface, the inner sidewall defining a first groove;

a first bearing component having an exterior cage opposing surface that defines a second groove, wherein the first bearing component is selectively inserted into the cage structure from an insertion position to an assembled position;

a lock ring that partially nests in both of the first and second grooves and resists medial/lateral movement of the first bearing component in the cage structure in the assembled position; and

an extractor pin having a first end and a second end, the extractor pin having an interference portion that tapers toward the first end wherein the extractor pin is adapted to be inserted between the inner sidewall and the lock ring whereby the interference portion slidably engages the lock ring and directs at least a portion of the lock ring out of the first groove.

28. The elbow prosthesis ofclaim 27 wherein the exterior cage opposing surface has at least one pair of tabs that are separated by a depression, the extractor pin locating at the depression during insertion between the inner sidewall and the lock ring.

29. The elbow prosthesis ofclaim 28, further comprising a plurality of extractor pins that each locate between a complementary pair of tabs arranged around the exterior cage opposing surface during insertion between the inner sidewall and the lock ring.

30. The elbow prosthesis ofclaim 29, further comprising a plate wherein the plurality of extractor pins are connected to the plate and concurrently locate between the exterior cage opposing surface and the inner sidewall during slidable engagement of the lock ring.

Images